Can't tell if lazy programming or just figuring it will fix itself. In theory there would be a point of overflow maybe? Well, I guess that also fixes itself.
Having a size cap does not make much sense since the increased pointer size is triggered intentionally, meaning if someone keeps shaking the pointer, they must want it bigger (whether for amusement or because they're hella blind).
Yes, it resets once motion is stopped. It's one of those things where without comments in the code or something you could also assume forgetting to check one of the bounds just happened to work fine.