"SNL". You mean Saturday Night Live"? If a child under 12 years old is allowed to be up that late, the child has some other, more pressing problems than television. Perhaps his/her parent(s).
My kids do not watch SNL, but they do stay up late occasionally and they are all under 12.
They stay up late when:
it's New Year's Eve
they have sleepover
we go to the drive-in movies in the summer
we do other family activities that are late in the evenings
I used to watch SNL when I was a kid. It was much tamer back then (John Belushi, Steve Martin days). I routinely stayed up until 12 on the weekends and during the summer, and nothing bad happened to me.