It did not happen to me, either, when I went through March 15 (#762 SFO-DFW). ID and BP were checked as I entered the line, but no check of ID or BP by the TSA folks either before or after the magnet. Of course, only two of the three magnets were open for business that morning and there was a long line -- the TSA supervisor was really trying to rush people along and through, so maybe they were too busy to bother with the additional checks then. It does appear to be very random.

P.S. They were also back to making us take off our shoes.