Everyone should ask providers of paid relays they use to allow anyone to publish receipts when the zap request came from a pubkey with write permissions. I just did this for our own relay the other day: nostr:nevent1qvzqqqqqqypzq8meqkx80g3yuklzymy0qfx2ekk56aqc2ht4ak03z3em4r4cdcwtqy88wumn8ghj7mn0wvhxcmmv9uq3vamnwvaz7tmjv4kxz7fwd4hhxarj9ec82c30qqsztfjrnvwjmnw2yq5rf2kwyq75plqfwsszp3txku0clhyp8h3068qd0jpp7