What citation and fine? What is the violation?
Basically, its coming down to that it simply is not legally closed. Not for nothing, but the closure in the winter months is no different than if an unauthorized person went there and put up a closed sign on July 1st and said it was closed for the summer.
I think most of us, at least in this discussion understand why and choose not to go. Its not about threatening people with fines and punishments that aren't going to be legally enforced. Either someone needs to go to the state officials and ask them to properly close it for a few months each year (and hope they don't in turn close ALL state parks to mountain bikers for the same reason) or it has to come down to educating people on why they shouldn't be riding there.
If there are people that want to volunteer their time and do trail maintenance than thats fantastic, but they are doing it knowing that the trails are probably going to be in $*&!@ condition because people ride there when the ground is soft. Maybe the signs and FB postings should be saying WHY its "closed" or suggested not to ride and offer a link to sign up and volunteer for maintenance and/or donations to help fund the maintenance. (I have no idea if its even appropriate to accept donations to fix up state property).
I do think the majority have been avoiding it, I've followed the posts on FB and do see people saying its closed, so its just trying to limit or educate the few that still choose to go, and if any of them change their mind about going, or offer up help, you're already ahead of where you are now.