Hmmm, interesting. I have seen plenty of cops out there but never with cyclists pulled over, or stopped for that matter. And I have never seen a cop on the trails on a bike. Plus they don't have a posted speed limit and the only thing on their sight is "speeding is prohibited" which is vague.
I usually am done riding before 10 am, so there is only joggers, runners, and cyclists out at that time anyway. I do know later in the day they get grumpy with fast cyclists as I have heard them holler over the loudspeaker in their car to slow down but that's been about it.