yeah, that's why I thought it worth asking. I'd probably make it a witness list, though witnesses could also publish their own records that pair with the witnessing. So: record.witnesses = [{ service: didString#Service, sig: #$bytes }, ...] Allowing a record to be witnessed by multiple services.
You'd probably also want to include the actor's DID and the collection in the signature too. Such that if I copy your record, it's no longer verified by the witness as being true