When in doubt, CC it.
Add cc@philanthropist.cc to the existing conversation. The email thread becomes the starting record for the matter and can be routed to the appropriate level of review.
Example
To: Counterparty@example.com
CC: cc@philanthropist.cc
Subject: Mobile Outreach Vehicle (CC)
We believe the activity described below is charitable under the stated facts...
Important: merely copying the mailbox is not an unlimited legal certification. The case record distinguishes receipt, acknowledged status, CC, conditional CC, review required, not CC and superseded matters.