Lest those who don't know me misunderstand, I personally won't ride a closed route. However, I totally understand why some do.
All I've read so far in this thread (and previous ones like it) is that there is the POSSIBILITY that someone MIGHT choose to ride down a trail that will damage a fragile ecosystem recovering from the fire. And all I've ever said is "then punish those who do, not those of us who don't."
Riding a 20 foot wide fire road will do no damage at all to any ecosystem. Heck, it might provide nourishment to the native fauna (think hungry kitty-cats). But riding on that road...or even down an established trail like Silverado Motorway...will do absolutely zero damage to recovering flora.
My point is that people know this. They won't do any harm on an established trail. Those who will ride off the established trails will do so no matter where they are, and they are the ones who should be punished for damaging the ecosystem.
As Mikie said above, if the closure makes no sense people will ignore it.
Sure, closing the trail/road makes life easier for the Forest Service...but they don't exist to make their own tasks easier, but rather to preserve access and enjoyment of the national forests. I'm a government employee myself, and the thing I hate most is to hear a typical bureaucrat say "let's impose this regulation. It will make our job easier." Screw that. That's not why we have a job.
Drop the hammer on the individual actually causing harm. The Forest Service's greatest ally is the average mountain biker, IF they don't do stupid, unreasonable closures.