I can't stress this enough, there is no reaction that would be an overreaction to this woman's lack of respect for her fellow passengers. I would say at the very least she needs every stand of hair that she carelessly flung over her headrest to be chopped off immediately, but if the person in 23B reached around with a ginsu knife and slit her fucking throat he/she would be completely justified in doing so. I have had other people's children crawl across my lap while I was sleeping and this is the most obnoxious betrayal of airline etiquette that I have ever witnessed. I have kept my mouth shut while sitting next an Indian family that didn't even dry the curry off their back after their last bath, but there's simply no passive aggressive act that would truly help this woman understand how disgraceful her actions were. There's no "excuse me ma'am" when you have blocked my 6 inch television screen from a row away. There's no pleasantries. There's no asking nicely. The only way to make sure this woman never does anything like this again is to do something she can't possibly forget, and I am pretty sure turning her ponytail into overhead storage does just that. If we are being honest, I am not even sure I would have the patience to think things through if that hair came flying off the top rope and tried to pin me to the back of my chair. I think I would instinctually pull it as hard as I could. Not because that's the most mature way to handle things, but because hair pulling is universally understood - much like the basic rules of human decency while airborne should be.