This happened to me once while in-flight!!! Some woman behind me (I was in the aft emergency exit row) started kicking my seat repetitively and pushing on my seat back. She never asked me to decrease my recline or anything, which I might have acceded to, so I completely ignored her. I finally heard her talking loudly about how unfair it was that I had all of that legroom in the exit row and that I was a jerk for not reducing my recline. She kept harping and kicking until one of her seat mates told her to stop, whereupon an altercation ensued. A flight attendant approached to see what was going on and the woman told her tale of woe and was politely informed that I had paid more than her for my seat, and that if she wanted a seat with more leg room, she could have paid for it. The FA said that, if she continued, she would be arrested upon landing for hindering the flight crew. The woman called the FA something nasty under her breath, but did finally quit her childish exercise. During this entire event, I never said a word or acknowledged her existence in any way. Upon landing, I got up and saw my antagonist giving me the stink eye, so I told her to have a nice day. Boy did she looked steamed.