The idea that there would be equal or more boosting if Blizzard didn't endorse it is fundamentally illogical.
Outside my window right now, a car that parked on the grass is getting towed. It's the first person that Ive ever seen park on the grass here. By your logic, they should take away the rules against parking on the grass because anyone who wants to park on the grass clearly does it anyway because this guy did. In fact, they should sell on-grass parking passes and the number of people parking on the grass surely would not change!