And when I was a teen, we frequently had parties in the woods (private property, not our own). Some had beer, some didn't.
As the leaders, we tried to pick up after ourselves, but I won't swear that we got everything. We did have cops chase us a few times. They had to cross a big field to get to where we were. It was pretty funny. They'd park, shine their lights up towards us and the fire. Get out and start walking. We'd watch them get about half way across the field, and then scatter into the woods, taking any alcohol with us. They'd get there, shine the flashlights around a bit, yell something like "we'll get you kids". Then they'd give up and walk back to the car. We were back around the fire before they made it back to the vehicles.
What were they gonna do? It's night, and we know the woods far better than them. If they search the woods and see one of us, we'd just run, and they weren't gonna catch us.
A neighbor (who was also a FB coach) caught us with alcohol once. He walked his dogs through the woods every day. Came back the next day, and I was in the yard with my dad. He stopped and said "It's such a warm day, I climbed that big hill, and by the top I was just exhausted, hot and sweaty. I sat down in a little clearing, and God must of been smiling on me, cause you'll never believe what I found. There were 4 unopened beers sitting there, still on ice!" My dad gave me a look, and then the neighbor said "I hope you don't mind, I drank 3 of em". And he wasn't lying.
I was grounded for a month. Moral of the story. Finish your beer!