It is a council-owned facility so they can make their own by-laws.
Fair enough.
It's not too hard to guess that the sign and penalty are there to protect aircraft owners from unauthorised access to facilities AND the visitor 's aircraft.
I have a personal hatred of Big Scary Signs. They never discourage proper law breakers who don't give a toss anyway, and just annoy/intimidate everyone else. A lot of the time (though not in this case, thanks for the info) they're not even legal.
