I thought about it, and did that once before in my lifetime... but value the friendship more than the rights to images I really couldn't ever use in the future. In my case it was their party, their daughter, and their memories. The value of "rights" to any of that is zero to me. The value of their friendship... and they express thanks for that and comment on how happy they were with the photos every time I see them... is invaluable. Oddly, I have never seen the photos myself.