I think your idea has merit. I would guess you think it would be a moral victory if your guild spent less. Or none. But I would like to see it taken further. I have always thought that listing who is boosting, and before the match, was a good idea. From my point of view it just gives you the choice on whether or not to boost in return (except in GCs). But there are 2 points here: 1) Boosters will always boost. 2) The money spenders will be protected.
It is moot either way. It keeps the money coming in and the spenders stay with the game. It is for us free players to hate and money spenders to never understand why.