I'm pretty sure it isn't legal even if they don't charge for it.
While there are nominative fair use rules for trademarks, that defense is generally used to protect simple uses of the trademarked word and not a trademarked graphical logo. Saying your Cola is "Cheaper than Coca-Cola" is fine (if provably true) even though "Coca-Cola" is trademarked, but including the Coke logo with its distinctive typeface and red color is not fine since it arguably implies Coke's endorsement.
It is possible nobody will C&D them over the social set (bad PR), but it is on very shaky legal ground and a C&D/lawsuit is far more likely if they charge for the font since having it be a commercial offering would likely offset a lot of the bad PR.
While there are nominative fair use rules for trademarks, that defense is generally used to protect simple uses of the trademarked word and not a trademarked graphical logo. Saying your Cola is "Cheaper than Coca-Cola" is fine (if provably true) even though "Coca-Cola" is trademarked, but including the Coke logo with its distinctive typeface and red color is not fine since it arguably implies Coke's endorsement.
It is possible nobody will C&D them over the social set (bad PR), but it is on very shaky legal ground and a C&D/lawsuit is far more likely if they charge for the font since having it be a commercial offering would likely offset a lot of the bad PR.