That is some genius marketing move; although an extremely risky one. How much earned media did Maker's Mark get over this? How many people will be buying their bourbon rather than a competitors' because they "decided to do the right thing"?
Lots of bourbon is sold at 80 proof.
How many people will be buying a competitor's bourbon because Makers "decided to do the wrong thing" and now, short of nontrivial research, one doesn't know what's in the bottle now?
There are a lot of other bourbons on those upper shelves.
And I still don't buy Belkin products because of that "replace random web-page requests with ads" router fiasco years ago.
..which, of course, would only be making the problem worse, so i don't think it’s a marketing ploy as high demand is the issue here.