Hello all, occasional lurker here.
In 2007, when picking up our bags in Leeds Bradford after returning from a trip to Amsterdam (Jet2 flight), both me and my boyfriend noticed our padlocks had been torn off our cases - the zip tabs were actually twisted and the ends were snapped off. It looked like they had been pulled off by pliers or something. Luckily nothing had been taken - I try not to put anything valuable in there anyway - but it's not pleasant thinking of someone ripping your bag open and rifling through your personal stuff! There were no Jet2 staff in the baggage hall to ask, and being knackered and wanting to get home, we decided to leave it. (We did have cheapo cases and padlocks, so it was a lesson for us really - will invest in something better next time!)
I know a few people have recommended cable ties - but couldn't they be easily cut off if someone wanted to open it?