[Lonman]

Like Billy i've never saved a list - I personally never understood the reasoning to need to as not the same singers come in night after night or even necessarily sing the same songs as the last time they were in. Always a fresh start every night - set to delete after played, don't remember a night where i've needed to play anything other than karaoke so no music or videos gets loaded at any time. If I see someone come in, i'll add their name to the rotation (which I have displayed on another computer) until they actually put up a song - learned never to assume someone wants to sing a long time ago so I don't automatically put up songs for anyone.
As far as someone that may be 'detained' when I call their name, I will not wait, I will get the next singer up & the skipped singer may sing after that. If they are not ready a 2nd time, they wait an entire round for their next song. Never let any song play until the end, once the ending credits of the disc display (unless the singer is doing some ad libbing over the outro) or until the singer walks off the stage when done, that song gets faded out & the next one is cued up.
I also have the no repeat rule for songs. 1st come 1st serve & after that it's off limits till next time.