Honestly, I think people exaggerate how common it was. On the most common controller layouts, it was quite difficult if not borderline impossible to aim your reticle at the face of a moving opponent and then mash B, X, and R quick enough before the other person moved their head out of your reticle. Even from 35-42 where you could find the most competitive games without also finding modders, boosters, and standbyers, I almost never experienced BXR. Very rarely did I ever see it in matchmaking. When I did, I'd just laugh at how badly I just got sh*t on.

Customs though... Anyone playing MLG customs seemed to want to get good at BXR. That's where it was common, at least in my eyes.

Now, BXB? THAT was common in multiplayer. And I guess I didn't have an issue with it.