yeah when those vans first came out there was all sorts of rules... they were only allowed to set up in a few locations which was very limited (for example, Adelaide Avenue between the lodge and kent St) but gradually they change stuff... it annoys me cos it's as if they think we're stupid and try to ease us into it so they don't get a big public backlash.
As soon as you accept one thing, they "up" it slightly, until it's like it is now.... speed vans pretty much sit anywhere and the signage is non existant.
As for cops, I have a friend who has just moved into traffic so I might try and ask her if there's some rules anywhere about what you mentioned Jayce. Being a bit of a revhead herself (drives a WRX, goes to bathurst each year etc) she's adamant she won't book people for doing stuff she would do herself... there should be more like her!