Booing is just rude, disrespectful and douchy. No matter who the band is. I have seen probably more terrible bands than good bands but booing them never crossed my mind.
That being said if it is a band that are total douches themselves or something like Nazi on stage then game on. But just for sucking or the fact you might not want to see them, that is just lame.
I also believe a lot the same people who boo bands are the same jackasses that will be all behind the band if the band makes it to a certain level.
Now if there were any bands I might like to hell at and maybe suggest they get off of the stage are those bands who grab every opening slot. They are like these pathetic rats going for anything and 9 out of 10 times those bands kinda do suck and no one wants to hear them anyway. This more so ends up being with locals of that respective area or region, there is always a couple. Often it is bands that don't even fit the bills they get themselves on.
Now I understand getting "yourself out there" but first have some fuckin dignity, and pace yourself too. So they are trying for all types of audiences or what ever; well death metal guy Warrant fans are most inlikely not going to be interested. I often wonder the logoic there cause all the band is doing is annoying people. But then again it is what I can only refer to as "band logic".
Think I'm getting of track.