If you think about the battle between Apple and the FBI about the cell phone you may realize that TSA approved has nothing to do with security, but perhaps them being able to get into it easily!
If you cannot afford to lose or have them stolen, I assume you keep them in your carry-on rather than check them when flying, so no need for TSA approved lock except when at the hotel. Perhaps a better option is keeping a secure lock, not TSA approved, in your bag and put it on after flying?
No lock will deter a determined thief, but to guard against the casual snooping or kleptomaniac maid, a solid lock with unique key should do OK. Could even get a cable lock to lock the suitcase to a fixed object in the room to avoid having the whole suitcase walk away if the documents are that important.
Most locks aren't very secure, more to keep the casual person out. I was reading an article the TSA has lost control of their master key somewhere and there are copies available online. Don't know if its true or an urban legend and haven't researched.
This has always worried me: thieves somewhere will always get their hands on (copies of) master keys. Or simply are masters on picking locks.
When I travel with big amounts of equipment, I simply plastic-wrap my luggage. That must really discourage thieves to try to open them up. And if security really wants to open it, they don't have to destroy my lock: simply get it re-wrapped.
Why for idiots? I use them on all my luggage. I occasionally find the notification from TSA that they opened a bag. I have a guitar case with a TSA lock on it. They've inspected that.
Never had anything stolen.
If you use a non-TSA lock they will simply cut the lock off and may or may not damage your bag doing it.
My advice for TSA locks, get the ones that have steel cable shackles. Too often, I have had the solid shackles bent. "Locks are there to keep the honest man out". I believe that, but still lock them.
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