Pre is the way to go. I was entered into the program by Delta without my knowledge. Now in any airport with a Pre line, I breeze right through. Leave the liquids and laptop in the bag, keep your shoes on and no x-ray scanner, just metal detector.
It's a mess. I haven't seen 'the attitude' very often, but I have seen it. I just keep a smile on and try to keep advancing. And I watch my iPad at all times.