Amiga Inc. don't own anything and KMOS has said nothing (I don't expect to hear any noise from that direct either).
Anyway, I see no problem with providing someone with an A1000 kickstart disk when they own an Amiga 1000.
If you have any concerns about this send an Email to KMOS, asking them to sue you.
Going back to your car analogy... You buy your car, but you replace the battery, You forget to note down the Radio code... The car manufacturer will provide you with the Radio code.