I've run across a few news sites with T&Cs like this. In those cases the goal appears to be preventing news aggregators from "stealing" their content by... linking to it.
Indeed. There are also lots of scanning services that go through websites to commercially exploit them. That's why you get these blunt T&C, which basically point out that you are accessing private property and need to ask permission.
An example might be a service that scans Eurostar's website for cheap tickets (i.e. loss leaders) and then consistently send (deep link) visitors who purchase the loss making tickets. While existing customers who are looking for the deal, can't find the cheap tickets, so become disillusioned.
