It doesn't seem to take much to Pi$$ off a karaoke crowd. And that's a pretty good reason. Delaying the show for a dart game.
The show must go on. Been the professional performers standard since before vaudeville. The owner is playing with her steady income and stands a good chance of losing it to stupidity. Take the show and the crowd across the street. They deserve better. The bar owner deserves a kick in the A$$.
You can't have your cake and eat it too. Make up your mind. Do you want to make good money from karaoke or do you want to cater to the dart crowd. Do it on a different night. You can't have everything going on all at once, without total confusion or interuptions of the singers. Those game crowds make too much noise to not be a distraction to the singers. Do you want to wait all night to sing and then have a bunch of yum yums making noise during your song? I wouldn't go back if that was the way it was going to be. And I wouldn't blame anyone else for staying away.