Walking into a high school when no one knows who you are is a safety risk for the students. You have no reason to be there, and are significantly more likely to cause harm.
Being kicked off of a public beach at dusk is arguable. I assume the law is there to protect your own safety. I am staunchly against this. An individual cannot infringe on their own rights--it's not possible. This is the reason I would NEVER agree to this law or similar laws designed to protect your own safety (seatbelt laws, etc.)
If you are causing a disturbance in city hall you may be infringing on the due process of the law and therefor the rights of the people to create law protecting their rights. This is different as well.
A military base is a safety concern. You are infringing on the rights of U.S. citizens by learning sensitive material which you could distribute causing loss of innocent life.
Sure they may be public property, but I never argued you could infringe on another's rights on public property, something John Bush, no matter how big of an asshole he was, wasn't doing when he was removed.
If nothing else, this shows how our rights are being stripped away, something John Locke argued would happen under a government.