At a Popes show several years ago, Shane was drinking a clear liquid throughout the show from a big pint glass. It looked like water. After the show, as the roadies were breaking down the stage, I asked one to hand me the glass (which I took home as my one, truly bizarre Shane McGowan souvenir). Shane hadn't been drinking water, but straight gin. He probably gulped two or three of these, in addition to swilling from a big bottle of wine. I doubt he was pretending to be drunk that night.
I expect as much from Shane this March. Though I got shut out of the first show, I hope I can grab tickets to the second.