My kit bag always comes with me as hand baggage and goes in the overhead locker or under the seat in front. It's well packed in a well fitting bag so unlikely to be damaged by other bags - besides, it damn near fills the locker so there's no space for anything else in front of it! Going through the machines, I've had to open the bags fairly often and had everything in there swabbed a couple of times. I don't have any problem with that - I'd far rather spend extra time being checked thoroughly than end up spread across the countryside. Sure as hell beats driving down to Crete too.