Vehicle security system tweaks
A more logical approach with more opportunities for roleplay

It would certainly make things very lively, but I suspect few players would want to invest in or use vehicles when their possession was so tenuous and likely to be quite brief.

Apartments and vehicles both have a certain amount of 'true ownership' that can be bypassed in some cases but through plotting rather skill checks, which I think is a positive for the player experience since it lets players feel their deep gameplay investments are more than superficial and not likely to be casually lost while they're offline.

I'm afraid those are not the only scenarios, and even if they were it would be an extremely low bar to meet to potentially lose possession of a vehicle forever.

Security systems have their quirks and are occasionally annoying, but my experience has been their protections outweigh outcomes where some characters dominate and control vehicle possession and access to the detriment of all others.

For instance: A vehicle being in a garage is not necessarily voluntary (or even known) on the part of the owner, and includes situations where the vehicle was taken from them, the vehicle was brought in by someone else who was authorized for operation but not authorization or ownership, or someone employed by a business who operates those vehicles, or where the vehicle did not have security to begin with by various energetic means.

It also does not account for not all vehicles being always vehicles per se, but rather hulks; whose ownership being determined by whoever got to them first would probably favor one or two characters to the exclusion of all others. Further any garage is not in any degree a limited or restricted tool, even though a specific garage may be.

That doesn't mean necessarily that things are perfect or could not be improved, but I do think that merely having to install a security system in a vehicle is simply too low a bar to surmount to determine effective ownership.

I appreciate it may seem initially like a difficult thing to gain temporary access or temporary possession of any vehicle, but over time I think it would become clear that the whole vehicle ecosystem and all the archetypes it supports exists now on the basis of conditional or temporary privileges which do not escalate except in very controlled circumstances that generally have staff oversight.