It depends on their setup. Yes, it is easy to view what various IPs have accessed and what not if they have some type of server/router that supports that kind of logging. If you have your own account to log in, it's that much easier to pin-point who's been viewing what.
However, if it's just a basic setup, say a cable modem and a linksys router, there's not much you can do to see who goes where.