This story doesn't give enough info to judge whether or not she deserved it! What song was it? How long was it?
On a related note, the only time I did Karaoke it was with my friend and we immediately got banned. Not because of bad singing though, it's because we sang "Do you want know a secret" by the Beatles, only our version was "Do you want to hold my penis"..and it was on family night (woops). But we had just watched a 15 year old girl sing a profanity filled Alanis Morrisette song, so we thought it would be OK. Too bad the manager was a lady because all the male employees thought it was the best karaoke song they'd ever heard.
I can't usually stand karaoke but I think I would cheer you on. Especially if you started doing your original bowel-tribute songs.