After trying out this tip a few days ago, I decided I would give it about a B or a B-.
I wasn't quite sure of a couple things: whether I should set the crock pot on low or warm, and whether or not I should cover the crock pot.
I left the rolls in for about an hour for about an hour and turned them a couple times so the bottom wouldn't get overly browned. They got nice and warm but Steve thought the bottoms were a bit too crispy and I thought the texture wasn't quite as good as I would have liked.
Still, if you really need to rolls warm and the oven is tied up, this is an idea that works. It just doesn't work perfectly.
If anyone else tries it, let me know how it goes!
(PS. From what I understand, this tip is for heating rolls that are already thawed, not for thawing frozen rolls.)