I've been using zip ties instead of locks on checked bags. It's usually just fishing gear, so help yourselves. I have way more than I need.
I'll tape a couple extra ties to the outside of the case, in case the folks looting inspecting my bag feel charitable enough to replace the tie.
More than once, my bags have arrived with the zip ties replaced... and my spares still in place.
I was pleasantly surprised that TSA would have (and use) their own zip ties.