I never had to remove my iPad in US airports (mainly MIA and LAX). Soon I'll be on JFK, and I'll be able to see how they do things over there.
However, on my return trips to Brazil I'm always
loaded with electronics: tablets, external hard drives, processors, video cards, etc. I guess the TSA becomes nervous due to the excessive number of wires and equipment in my bag, and I always have to unpack everything so they can check it out. Security theather