Attribute on the account and the sequence, not only the individual who replied. A prospect forwarding a link to a colleague who books is the normal case, so match the booking back to the account's active sequence and stamp both the person touched and the person who converted.
Without that, outbound looks like inbound whenever the champion hands off internally, and BDR credit disputes follow. Capture the sequence membership on the account, and keep the original source immutable so the later self-reported channel doesn't overwrite it.
Every claim above comes from work LeanScale published. These are the sources.