I don't see the issue with this, per se. To know that a unique person, identifiable only by their phone's MAC address, is going somewhere, is not really infringing on anyone's privacy, not at least until you attach a name and personal information to that.
If they kept it on its own, and used it, as Nikkom said, just to provide location-based advertising, there'd be no issue.

Monster Hunter: pissing me off since 2010.







