UA told me several years ago that they did not have to reimburse me when they broke my lock to get into my bag. They said that they have a right to search any checked bag at any time. They suggested that I use a common brand lock with a key because they have a lot of master keys that can allow them to get into a bag without breaking anything. The lock they had broken was a relatively expensive combination lock. Eventually they did send me a coupon for $25 off of a future flight.
I don't know what the current airline philosophy is, but when I check a bag I now use a cheap Samsonite lock that is just intended to keep the bag from accidentally coming open. And I never pack anything that looks (or is) valuable. Good luck.
[This message has been edited by Westcoaster (edited 02-05-2002).]