I've looked around the internet for a solution to this myself, and I was never able to find anything. The closest I found was that Songster lets you download their tabs if you know where to look, but UG really don't want people downloading their official tabs. An old post on their forums complained about it, for the same reason you and I would, but the staff response was that they think people would just repost the tabs for free in other places, making the Pro sub worthless which, yeah, that probably would happen.
It sounds like a lot of work, but I've actually charted a handful of songs from UG tabs by just copying them by hand. It's not convenient (and their official tabs often have small errors in them anyway), but it's worked well enough for me.