Ed may have tried Rain delay in auto. I have only tried it in manual. I can report that is stays on 0% on that setting. We have had so little rain, it is hard to test various conditions and settings.
Regarding enforcement, on peons like myself there is no enforcement except for random warnings. The value of the fine would to be worth the bother. In Ed’s case with 68 acres or so under management, he might be no be so lucky.
As far as how the cities might develop an enforceable reference point, I don’t know and I doubt they do either. It probably would turn into one of those guilty until proven innocent things. That’s one of the really cool things about opensprinkler: the log.