I've been out of patrol for over fifteen years. Last call was the worst (let's leave it there).
Yeah, I caught some. Caught a big group once. Prearranged, the whole nine yards. Let 'em go with a warning. They took some pretty intelligent precautions for the site and they also knew they were had. Nobody was a jerk.
I've NEVER charged anyone with street racing. I'll be honest though, I had some dead to rights and IF they had smarted off, then I would have. But to a person, they all knew they were caught, wrong, and accepted the fact like a man (never caught a woman racing). I respected that and thought seizure of their car (mandatory on my part, if I charged) was way too strict a punishment under the circumstances (prearranged racing) or that a verbal "preaching" was good enough for the spontaneous bouts.