I just read this on another site and found it interesting...
I was planning on getting one of those combination cable locks.
Recent problems with an expensive combination lock on a suitcase were solved by popping open the lock with one twist of a screwdriver. And if I can do it, so can anyone.
Furthermore, on investigation, little mass-produced 'travel' padlocks that you can buy from travel carousels at airports and in many shops all used the same key. Thus any half-intelligent, thieving baggage handler/room maid would need to make only a small investment in a couple of popular keys [e.g. the 'Go' brand] to get access to many cases.
Moral: Don't use combination locks and buy your padlocks from a locksmith beforehand, including a spare, and check they require different keys to open them.