I haven't been by my area yet, but when I called to double check the price of a permit, the guy that answered was knowledgeable. I don't know if they are affected by the shutdown though. I would check the wording on the sign too. It may be to keep non-permit holders out (ie I don't think you're not trespassing since you have permission to be on the land). I know parking is an issue for a couple of spots for me.
One thing duck hunting has taught me is that in prehistoric time, I would probably be a gatherer.