@nicholasalamprese . . . it does not happen very often but occasionally it does and mine has not even wandered off of the mat. It last happened to me when it was dark and something woke him up. He decided to walk to the far end of the mat and did not get back on his station before his battery ran out.
One thing that stops him from going too far is he has “walls” made out of boxes completely surrounding his area.
If you build an enclosure that will prevent him from potentially falling off the surface, it is not a big concern if he shuts off after going too far away.