I know what you mean. I have sat through some dire performances, including one who introduced a song as being "his version" and went on to sing from a sheet, out of tune, out of time, as though he had never heard the song before. I also have to remember that I sounded not far off that once. It is all very well saying you need to practice on your own until you are competent - but that competence then goes straight out the window for a lot of people when they have to face the public. I agree with the idea that different nights should serve different purposes - sing-arounds for all, guest spots for chosen performers, and when the club is crowded, up to the MC - some of whom will do a first come policy, some will do who haven't we seen in a while, some will do their mates, and some will do who is any good. The other approach is that in my area there are enough clubs that I can almost guarantee the kind of night I will get at each club. One club is frankly scary in the quality of the regulars, and anyone who went there for the singaround who wasn't any good would probably not go back. Another club is extremely egalitarian, and some of the regulars are frankly awful - I have tended not to go to that one very often. The club tends to get the clientele it caters for.