What other possible purpose, then, than a very deliberate, public show of force making it clear to all witnessing the spectacle that those who will not submit quietly will be made examples of?
I reported a few weeks ago about a TDC thinking that a German and Swiss passport were 'cool' and how he wanted to make copies for 'training purposes'. I responded firmly but politely why that was not an option, and continued through the checkpoint.
About 30 minutes later I was sitting at the gate, and three TSOs appeared to stand about 3 metres away from me. I will admit that my very first thought was 'they have come for me'. It was in fact a gate ID check, but made me rather nervous, even though I had done nothing wrong. (And in the end, they didn't check
my ID)
My experiences and more importantly the experiences of family in the DDR make me nervous at any checkpoint, even though I logically know that I should have nothing to fear.