In the forestry park where we hosted there was a total ban on alcohol, but everyone including the LEO felt that if you were discreet, we didn't know what was in your glass. Now if you were sitting with a beer bottle/can they would issue you a tickets. One guy had a 6 pk on his tailgate. The ranger even mentioned to him it was illegal to have alcohol in the park. Walked away so he had a chance to put it away. He didn't. 5 min later when the ranger came back by, there it still was -- so that man got a ticket. You just have to be discreet and don't cause any problems.