To add to this very interesting thread, I was recently (lightly) grilled at AMS due to the stamps in my passport - "You seem to come to Europe a lot?" "Are you working here?" etc. Friendly but somewhat unexpected. With family in France and a penchant for weekend breaks ex LHR my passport is quite stamp heavy post brexit to be specifically questioned was a bit of a surprise. As ever, staying calm and polite is the approach here.