Take Geri Mitchell of Seattle, for example, whose bag went missing for the entirety of her four-day stay in Hawaii for a wedding. The day she arrived back home, a Maui airport employee called to inform her that her belongings had been sitting in the lost-luggage office there for a week.

"For five days, not one person who works there bothered to read the very obvious ID tags and call me!" a still-incredulous Mitchell noted. Michelle Buchecker of Chicago, whose suitcase vanished during a six-day, multi-city business trip in 1993, is very angry about this. She had to buy new clothes when she landed. Oh, and the missing bag? She never saw it again and is among the tens of thousands of air travelers each year to have their luggage lost forever.

It's simply that, if a suitcase can't be reunited with its rightful owner within 90 days, the contents may be donated to charity -- or, more likely, shipped off to the Unclaimed Baggage Center in Alabama, a sprawling, 40,000-square-foot store where eager shoppers snap up lost treasures (maybe even yours) at bargain-basement prices.

So how does it get to that point? Though none of the following four scenarios are common (last year, airlines only mishandled 12.07 bags for every 1,000 passengers) they are among the most frequent reasons bags are lost, according to various airline officials and fliers' rights groups.

Scenario #1: The routing label gets damaged
Cause: When you check your bag, it gets tagged with an oddly printed, illegible routing label -- or a legible label gets snagged and torn off your bag shortly after being tagged. Adding insult to injury, it's a new suitcase, and you've forgotten to fill in the cool, leather-bound identification card.
Effect: No one notices the missing/unreadable tag until the bag has gone through TSA and arrived in the hectic distribution area. Because there's no way to tell where the bag should be headed, it just stays put. After arriving at your destination and waiting in vain for your bag to appear on the carousel, you file a report at the local baggage-service counter, providing a solid description of the suitcase. You're told it's going to take a bit of searching, so you continue on without it.

Scenario #2: You forget to pick up your luggage upon landing
Cause: Maybe you're distracted by an urgent text upon landing at home, and head straight for a taxi. Maybe you're weighed down with heavy carry-on bags and forget you checked once more. Or perhaps you're a tad buzzed from in-flight cocktails. Whatever the reason, you walk straight past the carousel and leave the airport without collecting your generic black roller bag (with no I.D. tag, natch), and don't realize it until you've arrived at home.
Effect: Eventually, an airline employee takes the bag off the carousel and stores it in the carrier's unclaimed baggage room. You call the airline and they put you through to an airport-based staff member who takes down a description and begins a search.

Scenario #3: The attendant types in the wrong destination code
Cause: When you hand over your luggage, the bag-check attendant accidentally inputs the wrong destination code. So off you go to LGA -- while your bag heads to LAX.
Effect: When you arrive to your destination and your bag does not, you file a lost-baggage report, giving a detailed description. The agent files it into the system and other agents are notified to be on the lookout in case an unclaimed bag fitting your description arrives at their location.Your suitcase sits in your airline carrier's holding area waiting to be properly identified. If it's tagged with your identification details, employees will most likely figure out where your bag was supposed to go and eventually send it there (or at least call to inform you it's been found). If it has no ID tag, it will sit -- and sit -- with the other unclaimed luggage.

Scenario #4: Your bag is loaded onto the wrong plane
Cause: You check your bag and, moments after it rides out of view on the conveyor belt, human error steps in: An employee places it on the wrong baggage cart, and, as a result, it gets loaded onto the wrong plane.
Effect: Even though the bag goes to the wrong city, it is properly tagged. So when it is the last piece of luggage on the carousel, an attendant will most likely see it, realize the mistake, and notify an attendant at your destination. The airline will then re-route your bag to where you are (hopefully without further incident), usually delivering it to your destination or, if you've reached the end of your trip, to your home.

How NOT to lose your luggage: Over two million bags were lost, damaged, delayed, or pilfered in 2010, according to "mishandled baggage" reports made by the largest U.S. airlines to the Department of Transportation. (That's about 3.57 reports per 1,000 passengers.) Here's how you can prevent becoming part of this statistic:

Double-check: Ask the flight attendant handling your bag if you can see the routing information placed on the handle to verify its accuracy before she sends your suitcase down the conveyor belt. This is especially important if you have a connecting flight, because bags are not always routed directly to the final destination -- on occasion, it may be your responsibility to pick up your bag from the first leg of your journey and re-check it, and the best way to confirm this is to see what's written on the label.

Make yourself known: The key is to ID your bag in multiple places -- outside as well as inside -- by placing ID cards in various pockets and pouches. And then add another, using the paper tags provided by the airline carrier. Be sure to include your name, address, and phone number (preferably a mobile number).

Share your plans: Pack a copy of your itinerary (in a place that's not too hard to find) so that airline workers will know where to route your bag in the case they find it and cannot get in touch with you.

Document the evidence: Photograph or video the contents of your bag as you pack. "I just lay everything out on the bed and take a few photos with my phone," said Kate Hanni, of FlyersRights.org. Not only will that help to identify your bag if it goes missing, it will also help with claims forms if your suitcase is never found.

Remove extras: Before checking your bag, take off any removable straps; this will decrease the likelihood of it getting snagged along the way.

Arrive early: If you check a bag within 30 minutes of your departure time, it may not actually make it onto the plane.

Stick to tradition: Finally, don't check your bag with the curbside baggage checker; go inside to the main counter to decrease the chances of a mix-up.

Embellish your bag: Whether you buy a colorful handle wrap or just add a few stripes of bright duct tape, making yours different from the others could draw the attention of a not-so-motivated airline employee. Another option is to purchase a bag that's not black or navy (like the overwhelming majority), making it easier to spot in a roomful of luggage.

Finally, what are your rights if your bag is lost for good?

In the event that your bag is lost for good, US airlines can be held liable for up to $3,300 for domestic flights. The airlines will not, however, simply pay you to replace your missing items. Instead, they'll decide the compensation amount based on original purchase prices, minus depreciation (this is according to the "contract of carriage," which you automatically agree to when you buy a plane ticket). Here is a ray of sunshine: As of August 2011, a new law requires airlines to reimburse passengers for checked baggage fees (typically $25 and up) when said baggage is lost.