There's a date given about Mac's and it's been there longer than Death Masks... well, what year do the books actually take place in? I think the date I saw was in the early 1970's... anyway, wouldn't it make sense that anyplace that is 'friendly' to supernatural types, i.e. the owner (or proprietor) knows of their existence, is not an actual member of any court or faction, and welcomes them in general, and is the sort of place that both (or all) sides might wish to frequent, would petition for the status?
I mean, if people wanted to go to Mac's back in the day, but he'd had to repair his place a couple times thanks to opposing parties showing up at the same time, and the vanilla authorities were possibly in danger of being attracted to trouble, that would probably trigger a need for it to get the status, as long as the proprietor was a responsible individual and has proven himself so (as Mac had/has). Mac is pretty darn careful to walk the straight and narrow about staying out of his customer's business. He just barely gave Harry a little help the one time, and I bet then he carefully considered if it would go against his neutrality status! It was more against a vanilla human opponent and not an actual signatory of the accords. (trying to remember what it was now, but I remember thinking about it at the time, and yeah, that was other than the case in "Last Call" BTW, and oh yeah, didn't they violate NG by doing that to his place and his Ale?)