Absolutely. I always check to to ensure nobody is behind me if I plan on reclining the seat. I also ensure my knee is in the way if the jerk in front of me plans on reclining. Better yet, I've seen they sell these little hooks that go over the tray table to insure that. As I'm in the ATH lounge preparing for a CE flight, I wish I'd already bought some.

Most of the time, frequent travellers are polite and understand. It seems to me it's AA passengers who transfer on to Europe who are not au courant.