Alignment techs?

I started working at a shop that has an alignment rack and I've noticed that when these guys do a 4 wheel alignment that they do not pull the pins on the plates that the rear tires sit on and yet they do adjust the rear. It seems top me that they cannot possibly get true readings or do a proper alignment if the rear tires can't float I want to question them on it but didn't want to look stupid but I really don' think that I am the stupid one