This was really upsetting to me - the Valmont bike park has to be closed to the public because of damage to the trails caused by people riding/running/etc on them in the wet/snow/mud.
Here's the thing (and I see this all the time at lots of other parks and trails as well) - in Colorado, if the soil is wet, being on the trails is going to trash them. Going around the muddy bits (always popular as well) will also trash them. And usually, your drivetrain and brakes will get mangled pretty well in the process.
So it baffles me when I see cars with bikes turning into the Marshall Mesa parking lot on a sunny 55 degree day after a big snowstorm, when everyone with half a brain is out for a road ride. Why does anyone think that riding in slush and mud is a good idea?
Feh. At this point, I'm all for closing any trail that's muddy, and handing out $500 tickets (or maybe impounding bikes?) for violations. At the rate things are going, there won't be anything but rutted-out triple-track to ride around here after the winter mud morons get done with it.