Yeah I also regularly bring a razorblade (for my old fashioned safety razor). I have got caught once but it's worth the risk of wasting a few minutes.

If this was really about security, it would be set up so that just deliberately breaking the rules for the sake of minor convenience actually had some consequences.

If I wanted to blow up a plane with liquid explosives I would just... Try a few times. If you get caught, throw the bottle away, get on the plane, and try again next week.