But we are talking about giving the recipient an incentive to fix their setup. "You would have received 20k sat if you had a working zap setup" is not the same as "setup your zaps wallet to claim 20k sat". The latter could be done with custodians which is dirty or with promises to pay which I love as a building block for other scenarios, too.

If you see it as a delivery mechanism of an error message that right now doesn't reach the one who can fix it, sure, but we can make this something more ambitious for zap adoption.