Sorry I read that too quickly.
Yeah you also can't trust the sender and receiver are not the same person even if you do trust the lighting service provider. But for my use case this doesn't matter.
Discussion
In my use case I just want to have a fairly strong guarantee that the receiver of the zap actually did receive the sats, even if they sent it to themselves.
I think there is one issue remaining with custodial zappers where you can pull off a replay attack, but this isn’t possible if you run your own node.