I checked carry-on rules at 75 airlines. The carry-on wasn't the trap

In Europe, they never, ever pick on this. Not a single time and i fly more than once per week.

Only problem is that flights are frequently full so they sometimes force me to check in what i should take onboard, and i hate waiting for checked in bags. And on turboprops, there's that 'delivery at aircraft' thing (while it's not as annoying, it sucks dragging bags around a dense, small aircraft).