Unfortunately, I've seen two sets of friends go through adoptions that were rescinded afterward because the parents wanted the baby in one case and older kids in another, back.
Another friend adopted from Russia and though there were certainly hurdles, at least they didn't have to go through the pain of returning the child under orders from a judge.
I think the way it used to work where things were kept anonymous worked better. I very good friend of mine was adopted and she never felt inclined to find her birth mother. Perhaps she's the exception.