I love older thinkpads and have one as myback up/secondary device. However given the reapeated malware issues with Less, I would never purchase a new one.
Tried this once with my old childhood cat. She hated it, and would wiggle out of the collar. What she would do is follow us around on walks in our suburban neighborhood leash free. She would usually stay a house or two behind us and run from hedge to hedge.
We were worried that she would follow me all the way to school, when I started walking there, but we tested this, and she would refuse to cross a big street on the way.
I used a raspberry pi, a controller board and a linear actuator to create a similar solution. I also coded up the door lock, but turns out the linear actuator has enough resistance to stay closed on it's own.