I love the idea, but it woths only if youi cannot just pick the vehicle up and occupy 1 slot. I actually would rather have a vehicle garage or assembly station that would fabricte the vehicle and deploy it and the player shouldn't be able to pick it up. This mod would be useful then.

Vehicles take up more than one slot if there is anything in the trunk, ammo and fuel slots. All those stay in the vehicle when you load it.

I usually play treating vehicles like you say, just by choice. I suppose you could add a mod to enforce no mining of vehicles.

FYI, Vehicle Wagon is compatible with Uncle Shred's Unminable Vehicles (https://mods.factorio.com/mod/UnminableVehicles) that will force you to drive, or train, your vehicles everywhere once placed.