Recently had a similar experience at MEM. Had to sit on a chair in view of all other pax with my shoes and belt removed whilst they were placed through the x-ray. Luckily the belt was more of an accessory than necessity so my dignity stayed intact!
ramsrc.
Also had to have the double security check at FRA a few weeks ago when positioning FRA-STN. Can't really see the logic when they're both identical and you are in a secure area after the first one?