To the people raising the question about the Sins of the Unforgotten:
I don't think switching dice is really enough to warrant one of those. Beforehand, Rob was doing things that blatantly violated the rules of chance and reason in the game (blowing on his die, moving a character to a place that he could not get to). People switch dice in real games all the time and the GM never calls foul on that. Something that would earn a Sin of the Unforgotten is if Mike said, "Oh look, I just remembered that I have (name of spell that Mike made up off the top of his head) that makes all my nat 1's nat 20's." THAT would be cheating. Simply switching dice is not.
I don't think switching dice is really enough to warrant one of those. Beforehand, Rob was doing things that blatantly violated the rules of chance and reason in the game (blowing on his die, moving a character to a place that he could not get to). People switch dice in real games all the time and the GM never calls foul on that. Something that would earn a Sin of the Unforgotten is if Mike said, "Oh look, I just remembered that I have (name of spell that Mike made up off the top of his head) that makes all my nat 1's nat 20's." THAT would be cheating. Simply switching dice is not.