I've seen that in several airports, and it isn't the TSA that cares. The airport owners will have done deals with the airlines, and the TSA's job isn't to decid

I've seen that in several airports, and it isn't the TSA that cares. The airport owners will have done deals with the airlines, and the TSA's job isn't to decide who goes in what order, it's to make sure that whoever goes through isn't breaking any laws. So if the airport says first class passengers go first, that's who the TSA check first.