Airline employees offer the following pieces of advice regarding loss/theft from bags and airline claims..

1) Do NOT pack anything that is high value like jewelry or cash or anything that is irreplaceable. This is just removing a temptation before it can become a problem. Remember, most airlines' Contract of Carriage (the legal agreement between you and the airline) usually limit or deny any coverage for many items of deemed 'high value'.

2) Take several time/date stamped DIGITAL PHOTOS of the things you have in your bag.. A suggestion is to take several digital photos of all your items-- laid out beside your bag-- before you pack it. This serves two purposes: a) It gives you a better "claim" as to items actually inside your bag and the conditon and b) the actual bag itself, should a loss/theft issue arise.

3) ALWAYS check your bags for signs of tampering IMMEDIATELY after reclaim. Some people put small, lightweight "zip" ties on their bags so they can instantly recognize if it's been opened. Others use special tamper-proof stickers.. Either way, make sure to check before you leave the airport. In most cases either the airline, the airport authority, local law enforcement and/or the local Customs agency has the legal right to open and inspect any checked baggage.

4) If your bag has been opened for any reason, CHECK the contents BEFORE you leave the airport. Basically, once you leave the airport, you are implicitly stating that everything's OK with your bag and contents. Few airlines will accept claims for loss/damage once you've left the airport premesis. If you do happen to leave, then discover the loss later-- call the airline immediately.. Time is of the essence.. Your claim will have much more validity with the airline if its filed on the same day versus a week later.

5) If you notice something is missing or damaged inside your bag, or your bag itself is damaged or missing, FILE A REPORT WITH YOUR AIRLINE (called a PIR- Property Irregularity Report-- an industry standard form) with the airline BEFORE YOU LEAVE THE AIRPORT. Some airlines may be reluctant about completing this report, but be persistent insure that one is filed. It's hard to understand why airlines don't like completing the report - the mere fact you filed a report does not obligate the airline to anything nor is it an admission of any liability on the part of the airline. All it does is state the facts: who, what, where, when and why.. It's up to the airlines' central baggage office and your insurance provider, (if any) to determine if there is a liability and if any compensation is due.

6) If you transferred from one airline to another enroute to your final destination. As long as you have not reclaimed your baggage enroute for any reason other than mandatory customs clearance purposes, it is the LAST airline (the airline who flew you to your final destination) that assumes ALL liability for any loss, theft or damage to your bag or it's contents. This is industry wide practice to simplify the liability-sharing formulas used by airlines. 

7) If you're overseas, GET A LOCAL POLICE REPORT. The airport police or law enforcement agency at the airport are really good about this.. Most foreign insurance companies will require either a police report documenting the loss and/or confirmation (your completed PIR) from your airline to settle any claim. 

8) Delayed Baggage Compensation: If your bag does not arrive with you, some airline may offer to reimburse you for minor purchases while your bag is lost or delayed. Examples may include basic toiletries, basic garments and such. Be sure to cofirm the maximum amount of reimbursement allowed, items that are eligible for reimbursement and the process for seeking reimbursement. Lastly, to protect yourself, you should attempt to get the airlines reimbursement agreement with you in print should a disagreement arise later.

Lots of people have successfully received proper compensation for baggage issues by following these tips.. Sadly, others who were just not informed and were denied seemingly valid claims due to simple lack of documentation and/or evidence of loss.