I agree that it's hard to imagine that the gropes are really about stopping terrorists, because leaving a suspected terrorist's stuff to mix in with other passengers' things makes no sense at all.

When I got groped, I was a female traveling alone, and I had to insist on being allowed to at least see my belongings. They finally gave me permission to stand in a place from which I could sort of see my things. I couldn't see them all the time, since passengers were going between me and my stuff, and at one point a passenger put an empty bin on the bin that held my laptop. Good thing it wasn't a bomb.