I've seen those robot mowers. It's an interesting idea.
Something tells me that there ought to be a better way than a wire border, though. Seems like it should be easy enough to "teach" the system about the border of a yard, and have it mow the remainder without bothering with the random-learning algorithm.
We've got some variants of that that we're playing with. They have rocket and grenade launchers on them too. :-)
Well, that'll raise the ticket price a bit, I reckon... ;~)
That should probably fix the theft problem.