Using the Rules exception "is on a recipient's supervision list"

In our tenant, I want to quarantine all inbound mail from gmail.com except for approved senders. Currently I do this with a Rule with an Exception:

Except if | The sender | is this person 

Users send me exception email addresses that I manually enter.

I notice that there is another option for The Sender called "is on a recipient's supervision list" I don't fully understand the Microsoft documentation on this option. It says: Messages where the sender is on the recipient's Allowlist or Blocklist. Does this mean each user can enter the desired exception email address(es) into their Outlook (desktop client) Allow / Block lists?

Any help to clarify is greatly appreciated.