In this case, swimming on the free beach is probably an infraction, much like failing to use your turn signal. The worst penalty you’ll face in the usual case is a fine. But if you swim on the free beach, get yourself in trouble, and a rescue party has to come save you, the fact that it’s a “crime” now gives the state the ability to recover their costs from you afterwards.
What would make it "a crime" as opposed to just being "illegal"?
Put it another way, people think if something is illegal, punishment for that must be a felony or something. But often times, it’s just an infraction so punishment is at most a fine or a minor action like getting kicked off the free beach
Recent examples are GDPR, where before it isn't regulated to track user information without consent, now being prohibited with clear penalty. Next they should regulate personal assistance like alexa and siri