Vast majority of the audience perhaps. However when you have a strong lead in, with a audience that doesn't watch your channel on a regular basis, its always a good opportunity to showcase your product, and maybe win over some viewers. ch10 didn't even try. Of course to be fair poor nbc10 can't catch a break. The ratings coming off that game here in Philly couldn't have been as high as NBC10 was expecting.
Still here's what ch10 should've done. Now i'm not fully aware if NBC would have allowed this anyhow. They probably wouldn't have. (Being a O&O is the worse thing for 10)
However I would have shown SNL on 1/2hr delay. Has the news, while promoting a special football night in Philly afterwards.