I added my kids to the family tree and personally don't believe that the only aspect of a family tree is to document genealogy. It's the family history too. If it were only about genealogy, then we would not include spouses that marry into a family. (not everyone has kids or maybe it's a 3rd marriage etc.)
As for the school project trees, we just asked that the "Send in baby picture along with your tree" be changed to "Send in your favorite picture of yourself" so that my kids wouldn't be singled out for not having baby pics.
When the geanology stuff does happen in school for us, I am not sure what we'll do then. Not going to worry about it though.
