Tron[ADS] said:
Forgive my ignorance, but what is "TSA" ?
"Transport Security Administration" - the agency that x-rays and searches your bags (and you and your hand baggage too) when you use air travel in the US.
You used to be able to lock suitcases that you checked-in at the airport, but this was changed after 9/11. Now you are not supposed to lock them, because the TSA want to be able to search your bags if they see fit (sometimes because they have seen something odd on an x-ray, sometimes because of random selection). If you lock your suitcase, they will cut the lock off to search it.
A set of "TSA Approved" locks have been developed where the TSA agents (at the US airports) are supposed to have a master key to be able to open the padlocks (so they don't need to cut them off). Unfortunately many frequent travellers have discovered that either not all agents have these keys handy or just can't be bothered to use them (so they cut the locks of anyway).
Some TSA agents will re-lock your case (or stick a zip tie to seal it), others wont. Some agents stick a note in your case to say that it has been searched, others wont. It is a lottery - which I think is bad: they should ALWAYS secure the case and stick a note in to say it has been searched...
The funniest story I heard from a frequent traveller was that when his suitcase arrived at their destination, it had SOMEONE ELSE'S TSA approved padlock on it! He had to get airport security to cut the lock off (because, it not being his lock, he didn't know the combination!).
The best airports are those that do the TSA searches whilst your suitcase is still in view: if they are going to search your case, they will do it whilst you watch, so you can lock it afterwards.
Personally, after my (and others) experiences of TSA locks, I am going to use zip ties.
Boo