Have you ever got caught when camping in Vanagon where you are not supposed to, and what was the outcome?  In over 45 years of VW van camping, only happened to me once.  I was in Zion, Utah.  Simpler times of course, decades ago.  I parked on the far edge of the parking lot at Visitor Center; enjoyed a wonderful guitar performance inside; went back to van.  Around 11:30 PM....that unmistakable knock-knock-knock of metal flashlight on window.  Red and Blue lights swirling around.  I stumbled outside.  Ranger said, "Uhh, you know, you can't camp here."
The outcome?  Ranger directed me to a back street in nearby town.  That was that.  And lived to tell the story!  In general, the law folks only want no trouble for anybody.  And since then, proliferation of signs informing of no overnight sleeping in vehicles.