Having the sender do it also makes sense from an auth point of view— thinking of like a private Github repo, or something like Jira running on your corporate VP

Having the sender do it also makes sense from an auth point of view— thinking of like a private Github repo, or something like Jira running on your corporate VPN. Presumably the sender intended to share the contents with every recipient anyway and any that don't have access still of course won't be able to click through. But it would be pretty bad UX if the card was just blank in these cases because the messaging server didn't have access.