There's no zap receipts they are more like payment targets its just reusing the same branding

I wonder if they publish true receipts or can they just be faked by publishing an event?

Zaps is the wrong word, I agree. It’s just a monero payment.

Doggie coin would work for public tipping imo. At least it has an actual PoW chain unlike lightning

Isn't lightning also private?

Yes.