Supporters of Prop 8 claim that even mentioning any marriage in schools counts as "teaching". So they are using that as a "Marriage is taught in schools."
They have yet to prove that Gay Marriage is taught in schools. Except for one class of elementary school students who were supposedly brought to a Lesbian Marriage.
I doubt that was the case though. I imagine they walked past, went to the church for something else... or if anything, it's the blame on the teacher and not a reflection of the school. In which case the teacher should be held accountable.
Actually I remember hearing about that. A class at a school had a field trip to a marriage. The key point is this however:
1. As in all field trips, permission slips were required and parents were notified in advance. So if a parent didn't want their child going, the child didn't go (there actually was one child who didn't go for this reason).
2. There is no information as to the background information surrounding the event. They likely had a good reason; otherwise, the school's administration wouldn't have approved it in the first place.
That aside, marriage is rarely talked about in school, if at all, and certainly not in curriculum. Usually the only cases that marriage is discussed are when fundamentalist religious schools decry homosexual marriage as sinful.
Anyhoo, it seems that that ad paid a ton of money, seeing five different versions of the same ad are the only ads showing up now.