booze mining

Booze mining is the practice of hiding a quantity of alcohol (and/or drugs) before the security goes up for an outdoor festival (say, like Lollapalooza) by burying it on the grounds, often with a geotag on the location, and digging it up after the show starts.

"What're you doing there?"
~ "I'm digging up my booze, man!"
"Dude, I so thought booze mining was an Urban Legend!"