When I arrived at JFK 2 weeks ago for a late afternoon flight the security line was backed up worse than I'd ever seen. I had to wait an unusual 20 minutes or so at the elite check-in area. By the time I got in line for security--and the elite line still took about 15 minutes-- the lines had gone back to nearly normal, and all the nude-o-scopes were blocked off. My guess is that the earlier back up was due to their being used, and that the NOS were temporarily roped off only to process pax more quickly.