We have some good discussion here. I think the worrisome aspect is the lack of communication the new owners have shown, and the fact that their restrictions "island" public property. Access restrictions on property vary so much that you must know the law for your locale.
I know that, in Oregon USA, one of the reasons that large land owners block off roads is the "adverse possession" clauses and such. "we've always used this road, so we must have access". Problem is when the road is damaged, used as a logging landing/loading, and the public insists that they must be able to use it. Liability concerns are sometimes overruling common sense.
I don't know what we, as a group, can do to help the situation, but this is becoming more an issue than in the past. More tracts of our state forests are behind locked gates than before. Not that they are locking the area, but transit to the area is blocked.
CT