An idea...

from Coz.  When we took them back to the airport after their holiday with us, I noticed that Corin used these little zip tags instead of a lock and key on their suitcase, and he used a coloured one not a white one.

So I am going to do the same with our cases on Monday.  I realise that if anyone wants to break into your case they will do, but having experienced an incident in America where security cut the lock off my case, then inspected the contents, and put the broken lock and key with a letter back in my suitcase, I was dumfounded.

Obviously nothing is fool proof, so I will give this method a try.