If the RTS behavior could limit
itself to certain kinds of objects or families for its travel, rather than just avoid them, I would probably use this exact approach myself. It's incredibly handy and consise, the way you've done it!
As it stands, I'm trying to solve basically the opposite problem, which turns out to be a bit more work. This is a nice bit of inspiration, though (yours too, toralord).
Oh, just one little suggestion: Movement's a bit smoother if you change out the "Every 500 milliseconds" condition for "If != Hunter 2 is moving". Assuming you don't want the pauses, anyway.