Possibly, but unlikely. That VPN connection is essentially a two way connection, so in theory it would be possible. In actual practice, I doubt it is. There would be some thorny privacy issues employers would have to contend with if they were caught pulling that kind of crap. Using a work computer, at work, is a whole different story from using your home computer, at home, to do some work. You'd have to find a pretty hard line neo-con judge to find that kind of thing acceptable.

If you're even remotely concerned about this sort of thing, either stop doing work from home, or have your employer issue a system for you to use at home. It's better to not even give them any sort of opportunity, because fighting it out in the courts later would probably be expensive, and get you blackballed in any industry for being someone who once sued their employer. Kind of a catch-22 on that one. Can't very well let them invade your privacy, but if you stand up for yourself, then everyone will always wonder if you'll turn around and sue them next. So, better to just make sure that the situation never arises.