Here's a solid example - in 2016 all teslas came with free supercharging for life. In 2017 they changed it to be non transferable. If you buy the car directly from someone tesla won't know but there has been cases where they've found out (warranty repairs for example) where tesla then removed it.
If the seller didn't tell the buyer, or the seller themselves didn't know - who's fault is that?
If the seller didn't tell the buyer, or the seller themselves didn't know - who's fault is that?