Saying no to people is awkward, especially for Minnesotans, and when you're in the spotlight and people are waiting for you to make decisions it can be even more difficult. But I'll go ahead and say it right now, for the future: "Just Say No".
We were getting to the end of the night and had played all of the songs in our set when someone in the band remembered the promise we had made to the lady from before. We called him up and everyone in the band looked around nervously.
The guy was perfectly nice, he had been hanging around and watching the entire set (he was hard to miss wearing a bright yellow day-glow t-shirt) and even when he got on stage he was quite congenial. He didn't speak any English, but luckily we had someone who could translate for us. It turned out that he didn't want to sing "Shout", rather it was "Jailhouse Rock" (I think). The Presley classic had been our first song of the entire 2.5 hour set so apparently he had been waiting around the whole night just itching to belt out a Spanish version. So after a bit of bumbling around on our packed stage we deciphered the song he wanted to sing, readied our instruments and played the first chords.
He was awful.
I'm not going to be nice and say that he "made a great effort" or some other Minnesotan platitude that sounds uplifting but actually hides the hideousness of the whole thing. He stunk. It may be that "Jailhouse Rock" wasn't actually the song he was thinking of, or it might just be that he was born with a charismatic personality and a scientifically incomprehensible vacuum where his sense of rhythm was supposed to be. The first verse went somewhat normally, but by the time the band was on the chorus, our visible-in-all-light friend was already yelling about a "gato on a saxafon". The wind left his entourage's sails at breathtaking velocity. The water went from lapping at his heels to being 8-feet deep. The excitement in his eyes turned to fear.
Eventually he ended the song and sometime later the band did as well. He said thank you and left the stage, and we played one last song to go out on a good note.
My anger about this experience doesn't rest solely on the man who sang. I have a feeling that his friend, the pushy lady, caught him singing along a bit and demanded that he force his way on stage. Or maybe it really was him, in which case his bombing serves him right. If pushy lady was to blame though, she's the worst kind of audience member. The kind that views the world as her play-thing.
Bands practice to play on stage. Often a lot. There's usually a long collective musical experience put together in a band and that experience is what makes it work. To demand that your friend gets put on stage is offensive to everyone who has worked hard to make the music work.
I've been in other situations where people push their way on stage. At a bar I played at a group of drunk 20-somethings demanded the tambourine from the singer and proceeded to play keep-away and bang it erratically. At my college after a recital, it was not uncommon to see other students go on stage and play the the pieces that had just been performed while people were still in the room, including the recitalist.
I try to be a humble musician, but if you want your time in the light, work for it. Make a band, learn your pieces, do whatever it is you want to do and perform, but don't shit on someone else's work.