Totaled Tesla sold for parts in U.S. came back online in Ukraine
cnbc.com
cnbc.com
So used car lots have tons of programmed garage door openers. If you have access to license plate record lookups, or you get lucky and find the person's personal records still in the glovebox (probably 25% chance at a poorly ran dealership), you'll be able to get into their house.
Tldr; if you leave things in your car, they become the property of the next owner.. who would have thought
Most use rolling codes, but those have a fairly small key space, which is further reduced by manufacturer IDs.