I just rewatched round six and I thought I saw Rahman sit on the ropes twice after the official knockdown. Remembering back to the Miranda - Pavlik fight, Lennox Lewis said that it was a second knockdown when Miranda sat on the ropes, but that one wasn't called either. What are the official rules in a situation like that? Obviously the ref has to see it...
Much like when the ropes hold you up, it's a rule but rarely enforced. Basically it's up to the ref's deicision.
I remember Larry Holmes had a habit of holding onto the ring ropes during his 90s stinit...that technically could've been called every time too, but no ref was going to start giving Larry an 8-count for that...