At the jurisdiction where I used to work, one of the incorporated villages had zoning, but they just didn't know what it was. It was what I call a microcity -- about 100 acres, with a population of around 300 -- which, in the early days of its existence, adopted zoning. However, there was no zoning map -- it was lost. There was also no known copies of the zoning code. Supposedly some associated party had a copy, but they had some sort of disagreement with the village administration. When asked to return the code, they didn't; rumor is that it was destroyed.
The village is built out, and replacing the long-gone code with a new code was never on the agenda; they didn't see the need. Of course, as planners, we can all predict what will happen years from now; some new resident will park an RV in the driveway as a permanent residence for their elderly mother, they'll start a very intrusive home occupation involving auto body work or machinery, build a chain link fence with barbed wire in the front yard, and propose an addition that extends to the property line.
Anyone else ever hear about a community that has "lost" or "forgotten" its zoning? Legally, what happens when there's a law in place, but nobody knows what it is?