I've been injured by a drunk passenger on a flight before. The guy was very tall and weighed a great deal. During the flight he came to the seat next to mine, collapsed into it with a thud and his elbow (which had built up a great deal of momentum) slammed into my arm and chest, bruising both. He didn't even notice he'd done this, he reeked of alcohol and his eyes were glazed. On my left I had a three year old child that I was solely responsible for.

I wasn't originally seated next to this passenger, the woman (who I'd helped out by storing her husband on the front row's luggage under the seat in front of mine) had switched her seat with the huge drunk man without notifying me. I was interacting with my daughter, oblivious, when I got struck.

After that, there's no chance I will ever agree to sitting next to a drunk passenger, particularly not when I'm looking after a child. Carrying a kid off an airplane when you've been injured and bruised is not an experience I'd like to repeat - I was lucky my arm wasn't broken.