Upend and drugs

I was at a convention today in San Francisco, and driving back, I saw a big sign on the wall outside a bar that said “We don’t allow drugs, we don’t support drugs, if you’re caught here with drugs you’ll be tossed, etc.” The name of the bar was the Upend. When I saw that, a had a recollection that someone here (Old Scratch?) told stories about people in SF “upending”, which meant going to the Upend and taking too many illegal substances.

So now I’m wondering. a) Is my memory faulty? Have I misrecollected the bar name? b) was that sign really to keep the law out, when within it’s really a drug nest? c) what’s the real story here?