Codswallop! to use the Nautical venacular.
Any area designated as a danger area is usually covered by local by laws. These are posted in local papers harbourmasters offices etc etc. These are enforced by range support vessels also I believe there was an informal agreement between the Castlemartin range with the guys from Brawdy who would mooch out beat up the offender whilst taking a few snaps for evidence.
A number of old salty dogs have been hauled in front of the beak and keel hauled, well at least fined heavily. Used to pop up regularly in the Tivyside Advertiser and Western Telegraph usually between the GBH and Driving offences in the court reports. The main culprits were usually Spanish Fishingboats allegedly.
I believe that repeat offenders had their watch keepers ticket removed.