Yes, at ORD in the middle of the evening rush-hour flight bank. Four TSO, two each testing both of the WTMD arches assigned to the Premier line. They held us in those two lines (refused to let us move to other lines with four more TSO standing around riding "herd" on us) for approximately 15 minutes while the performed the test. One TSO monitored the WTMD while the other walked/waved through a large block of metal at various heights and speeds.