Coetio transcripts carry a verification code. Enter the member's email, the total shown on the transcript, and the code printed at the bottom. If they match, Coetio issued a transcript with exactly that total for that email on the date inside the code.
What this does and doesn't prove: a match means Coetio generated the code for that email and total on that date, so the printed total hasn't been changed. It doesn't independently audit each entry; individual entries are approved by club leaders inside Coetio. This check reveals nothing else about the member.