Mark; this suggestion (or related suggestions) have come to mind following the "GDPR" thread on this forum.
I first came to Groups.io when a Yahoo Group of which I was a member migrated over. Since then a second Group came across, followed in December when the Group of which I am a Moderator moved over.
If this is the case, then it might be better if everyone coming to Groups.io for the first time was required to tick a checkbox confirming that they had read (and understood?) both. I would suggest that the preamble to the checkbox provides links to both documents.