If they have a gate change at FRA, they march the passengers (100+ when I saw it done) back through the "insecure" lounge area, and then bypass the first security check queue by simply herding people through a door beside the checkpoint, without going through the search or X-ray.
Any who protests at this absurdity, comments too loudly to a neighbour or even laughs in a particularly sarcastic way, is threatened with being offloaded for being disruptive. Several of us were so threatened.