I have to disagree with the opinion of thinking that greys who have been handled/touched should be forced:
"All of these places recommend that some type of physical bonding be started in order for the birds to calm down."
I believe the STRESS of being approached physically when the bird has no need or interest is damaging to it's trust in us, and has the opposite effect of "calming down." And let's face it, if the owner is not aware of improper petting/stroking, then the bond becomes that of a mate, and you start all sorts of trouble!
We need to recognize that we really don't know 100% of what these wild animals need. They operate by instinct b/c they are not very far removed from their ancestors. Until we remember that, I'm afraid the human's need to stroke will outweigh the need of the bird, and we will continue to find them in rescue situations. Not because we haven't touched them, but because we HAVE TOO MUCH. It's all very scientific and hormonal, and we can't begin to understand it.