I have often experienced a variation on this sort of theft. The people who have coach tickets who stow their baggage in the overheads in the higher class of service. Twice I've gotten on flights in the past 2 weeks and all the bin space above my seat was full. All! In my best loud voice I said, 'there is no room for my carry on bag.'

I think I ran into Mike out of BOS as the FA sorted out baggage and pax. He announced that anyone leaving baggage in the forward rows would have to come forward to claim it or it would be removed from the airplane!

One man came forward and claimed 3 bags from overhead bins. 3!

Thanks to FA's who protect their pax.