The signs on my nearby trail say something like "Bike path closed at sunset, commuters allowed" This helps get rid of the kids hanging around and causing trouble. And the commuters do not get bothered by the police. It is patrolled pretty well. I ride on it even after midnight all the time. The police watch me go by alone with good lights they know I'm prepared for the dark and not going to cause any problems.

The only time I have been stopped is when the police were looking for someone who was trying to escape down the path. They just wanted to know If I saw anyone. I think this system works as well as anything could.