I've seen this on Ubiquity hardware as an option too. Apparently it requires you to "check-in" via facebook to use it, whatever that means exactly. There is also an option to login via facebook without this though.

This was awhile back and was particularly nasty. No token, no check-ins, it was an unapologetic man-in-the-middle login prompt.

Terms of service had wording that made mining all data in your Facebook account sound like the intent.

How about no. Or hell no. If I see a request like that it is an immediate disconnect. Might as well have a requirement that they do a full anal cavity sweep before they can sell you a cup of coffee.