There are legitimate reasons to do things like this. For instance, my university (NC State) library interfaces to several journals in this way. Basically only campus IPs are permitted access, but you can log in from an outside computer with your student/faculty ID and use the journals.
That's the exact situation. The university lets us log in if we use their authentication system so it seems legit to just serve a little more easily so the users would only have to authenticate once. Some people have recommended squid, though I'm not sure. It seems like it would be hard to preserve the browsing interface while allowing searches on the journal sites. There are other problems too. Seems tricky. But as we all have accounts, I'm less concerned about intellectual property. joshua