Flopping Reference

[Rob1968]

BillyMac,

I agree that the defender can always move backwards. The subject of moving backwards when contact is imminent is only part of the legal movements of a defender.
Last season, working a three-man crew with an experienced partner, and another official, with considerably less experience, the younger official, from Lead position, called a block when the defender, who had LGP, recoiled upon imminent contact from a driving ball-handler. At halftime, when I asked him what he saw on the play, he said, " The defender was moving backward and he wasn't "set"." So, we had a discussion, which seems to fit the OP. He didn't want to accept my point of view, that the defender always and certainly on the play in question, has the right to move backward. But, a few days later, he came to me and told me he understood it better.
I'm sure you've heard, from the fans, and from coaches, the "He wasn't set! He was moving!" kinds of retorts, on such calls. Sometimes it seems they want the defender to "take it like a man" to get the charge call.