Considering it was a setup from the beginning, if he was really going to whip out his dick, they wouldn't have interrupted him right before the most incriminating part. They also had cameras, so this pick and angle was almost certainly the picture that they felt was the most damaging. Again, if RG was going to actually whip it out and get it on, they would've been insanely stupid to interrupt him before he actually started to get undressed. Even him in his undershorts could've been damaging.

Their story just doesn't make sense considering all the other factors.