But the thing is authenticating through Facebook probably does verify the vast majority of their customers' identities. Even if they put big signs out the fron

But the thing is authenticating through Facebook probably does verify the vast majority of their customers' identities. Even if they put big signs out the front of their shop saying : "You can make a fake account and use our WiFi if you care about your privacy." Most people would not go through the trouble of making a fake account and just login with their real account. The fact that the clerk was in conversation with this guy probably put him in the "non troublemaker" category in the clerk's mind anyway. And thus the whole identity verification thing was irrelevant, he was just suggesting a practical solution to the customer's problem.