My advice: Always take anything valuable out of the bag before handing it to complete strangers.

This is my story from about 2 years ago: I was flying back home to Montreal on AA, BOS-LGA-YUL. The BOS-LGA leg was on an E-190 in first class. All i had was a small carry-on bag with me. i was one of the last people to board, and naturally the overhead bins were full. The F/A offered to take my bag and put it in the hold. She said, "you can pick it up at the gate at LGA". I accepted, but before handing it over, i took my passport, money and keys out of the bag.

When i got to LGA, my bag had disappeared. Long story short, the brilliant mind i handed my bag to, at the aircraft door, from inside the aircraft, managed to put it on a different aircraft heading to DCA... To this day, i still don't know how one can achieve getting lost between the cabin door and cargo door of the same aircraft and ending up at a different aircraft.

Had i not taken my passport, keys and money out of that bag before handing it over, i would probably still be at LGA, probably begging for change so i can buy a ticket home...