Only two. Less than two for anyone not traveling through Las Vegas or Boston Logan, where the gropes were "tested" for months before being imposed nationally on November 1, 2010. People rolled over. As they are still doing. As for using the scanners as primary, always intended in my book. A friend just came back from a business trip to San Francisco. When she went to the airport there, she said everyone was being told to go through the scanners. There was no metal detector option.