Any such infringements would be illegal, as clearly specified in our newly passed legislation. In our state, don't worry about no gun signs. They mean nothing. I can't speak to the wanding/metal detectors, other than they would be illegal to implement at a public park, but that doesn't mean they won't do it anyway.
From what I understand, if you are carrying and they have detection devices and catch you carrying, you can't get in trouble for it. They'll just tell you that you can't enter with the gun. At which point you can make the decision to either just leave altogether or go put the gun in your car and return. But I understand the desire to want to know ahead of time.