Since this thread opened, I have been paying a bit more attention to the fundamentals underlying security checks at FRA. The other day, departing for BLR, there was only a single check - as usual. So, there is no connection between Schengen and non-Schengen states when it comes to single or double security checks.
However, I was surprised that men are without exception asked to remove jackets, whereas women can pass through wearing heavy trouser suits. Logic?