I'm six foot three and I've a simple rule: I never recline, so I never have to wonder. Doesn't mean I'd stop you. But I've watched a grown man get a drink poured on him over this, Ryanair to Malaga, and the lad who reclined was in the right and still went home with gin on his shirt. Right doesn't keep your shirt dry.

Let me take the side of the guy in front, since this thread is mostly knees. The seat is engineered to recline. Everyone on the plane has the same button. The social contract that says "don't" is a rule invented by the row behind, enforced by passive aggression, and it only exists in economy. Nobody in business class is writing these threads.