When the house lights went down, anything beyond the edge of the stage was pitch black. So it was only at the end of the first set that we discovered we were playing to literally no-one. (Well, apart from the bass player's girlfriend.) It had occured to us that the audience was very quiet, but as acts they didn't like normally had abuse hurled at them, this was something of a relief.
Seeing that we had no audience at all, our leader emitted the immortal phrase: "Well, let's treat it as a free rehearsal, shall we?"
The landlord said something similar at the end of the night, as he surveyed his almost empty pub, except with the added suggestion we didn't return anytime soon. Fortunately, for us that was an 'unusual request', lest anyone think I've drifted hopelessly off-topic.