This is the first time I'd heard of this rule. Being completely honest, on first look, it seems completely nonsensical. I'd much rather go up against a 70 grouped with his 79 friend than a guy constantly using saltwater and other misc. consumables. If people want to have fun with their friends then let them, it's not like this ladder is the most serious rating system in the world to begin with.
Looking at the vote it seems the people have spoken, though.
Edit: If playing with a chill 79 gets me disqualified from the ladder, so be it. 2 words on a website before my name isn't worth abandoning somebody who just wants to play a few games.