On another forum with a high volume of traffic, I posted the same question. If I remember correctly, only one guy posted that he had been stopped - and that was for a triple tow.
Based on watching several forums for more than 6 years, I would classify any RV stop other than normal moving violations (speed, red light, etc) in a category I call HBL (hit by lightning). What I mean is that you have a better chance of lightning striking you while you are standing in your backyard than you have of being stopped for only an RV related matter. Most LEOs won't mess with RVs because there usually isn't any place to get them off the road safely. As a group, RV drivers don't make the hit parade on statistically bad situations. LEOs usually have bigger fish to fry.
If it is a slow day and city revenues are down, all bets are off.