Mine had a pin number that you had to put in to start it, so stealing it would not have been easy. It could be programmed to run at a set time for as long as you wanted (but it needed to have rests built in for recharging - as we all do!) You could set it to go daily, or on certain days of the week, or weekly. I was very pleased with it in general. The grass looked good and I never had to cut it.
It didn't mow in parallel lines, but bounced off the boundary at an angle, so it traced a rather random path around the lawn. It did a good job, best if it ran a couple of times a week, as the clippings were left behind as mulch, and if the grass was longish they built up. They recommended that the first cut of the year was done with a conventional mower in case the grass was long and rough, but if it had been cut late in the autumn the previous season, I don't think it would have struggled with it.
The minus side is that it had to have a wire embedded into a slot round the lawn a couple of inches in from the edge, to let it know wirelessly that it was about to head into the flowerbed and that it had better turn. There was also a "lead-in" wire going from the mower's contact and recharge point to somewhere on the peripheral wire. That was the most difficult part of the installation, not helped by animals (I think foxes) digging up some of the wire in the first few days and chewing through it. Apparently they liked the taste of the plastic covering on it. A bit of wire had to be added in to join the ends together, using two sets of connectors and then burying that bit of wire again.
Then there was a problem when something (I think the moss scarifying done by Green Thumb) must have cut the wire at some invisible point. There is a procedure to find exactly where the break is, but it was complicated and time consuming, and I decided it was simpler to just lay down another wire, an extra inch or two in from the edge. I think I must have had the two wires touching somewhere, or maybe just near enough to each other to communicate, because the scheduling never worked properly after that, and it insisted on stopping dead at certain places and refusing to start up again.
I ended up giving it away to somebody who knew someone who they thought could mend it, while I bought a conventional rechargeable electric mower. If I were buying one again (and they are very useful things) I would get the work of installing it done by a professional, and if there were a problem I would get them back to fix it, I wouldn't do it myself. I would avoid Green Thumb, too, or anyone else who used machines on the grass.