How does requiring passwords tie the user to the device? Sure, in a house for example, you have assurance that the only people connected are your family (or friends). But if you're at, say, Starbucks (and they change the pass every day), the only thing you'll know is that people connected visited that day.

If you require a username and password to access, then sure, you could track who is visiting what websites (provided you don't allow guest/guest like my high school did).