I would presume that most coffee shops have no idea that CALEA even exists. The airport question is a good one, though -- they've obviously pretty security-minded (however poorly they may implement said security), so I would assume they've found some middle ground that allows them to offer "anonymized" access.

Of course, any paid access immediately associates a name with an IP: the person on the credit card used to charge the access.

So you're telling me a big chain like Panera breaks the law and nobody says anything?

Except if you pay with cash.