My sister and I have talked about donating eggs multiple times. We always go back and forth, because we can't decide how we feel. (We talk about a lot of different ways to earn money all of the time lol.)
I have never thought about it like this. I know some people donate and choose to be no contact. I think when the child is eighteen they can find out. That way they never become your responsibility. I don't know how true any of that is, but I read that at one point.