This likely depends on what state and what park you're in. I've travelled the US in an RV and I've definitely seen people scolded for simply enjoying a glass of

This likely depends on what state and what park you're in. I've travelled the US in an RV and I've definitely seen people scolded for simply enjoying a glass of wine in a state park. Lots of parks also have huge signs all over the place warning that alcohol is not allowed, so presumably they are taking it seriously.