After having worked some scrimmages, and looked at some old game video, I honestly think the BSB rule will eventually get "adjusted." I have seen two examples of what, by the current rule language, would definitely be considered a BSB. But, in both cases, the player being blocked is committed in a direct attempt to tackle/block the BC, when he gets hit by a teammate of the BC - yes, from outside his field of vision, and forcibly. With the rule as it is, the teammate of the BC has two choices: 1) attempt to help his BC - and his team - by committing a BSB, or 2) ease up, or give up, virtually guaranteeing that the defender will make the tackle/block on the BC. Choice 2) will really look good in the film room on Monday. "Why didn't you help your team? You just let that guy hit our guy!"
If enough of that happens, we may see an exception for a block on an opponent that is committed in his movement and intent, and in an immediate and direct attempt to tackle or block the BC.
Just my thoughts. Foul for now.
Robert