There are actually a couple of things that come into play in these scenarios ...
Sparky said that his band was supposed to be the attraction, and if that is the case all other 'attractions' should be eliminated ...
The reality is that most of the time - especially in a restaurant setting - the music is an 'add-on' ... perhaps some people are there because they know the person or band that is performing, but most people are there for the food, so we have to 'rein in' our egos and accept that as fact ...
In a lounge/bar setting more often than not there is going to be a TV with some sports game on, especially if it's the local team ... This is the situation even in the upscale Italian restaurant I sometimes sub at ... In the lounge, there is a small TV in a corner, in eyesight of about 95% of the room ... the TV is always on, but the sound is off ...
It's never right for the sound to be on while musicians are playing, because while some may want to WATCH the TV, others may want to HEAR the music ...
One thing that should be known by the musicians at the outset is 'who is in charge of the TV', and whether or not the sound is going to be on ... for the bartender to decide this is improper unless he/she is the manager or proprietor ...