Two kinds of email, and the line between them
Transactional mail is the mail a member needs: their invoice, their receipt, their renewal notice, their sign-in link. It goes.
Commercial mail is the mail you want to send: the newsletter, the event promotion, the appeal. It goes only if you are allowed to send it.
Sembr treats these differently on purpose. A member who unsubscribed from your newsletter still gets their invoice, because an invoice is not marketing and withholding it would be the wrong answer.
What Sembr refuses to send without
A postal mailing address for your organization. Set it in settings. Until it is there, a campaign cannot send.
That is not us being cautious. Commercial email law in Canada and the United States both require a physical address in the message, and a campaign without one is not a slightly imperfect campaign, it is an unlawful one.
Consent
Every consent record is append-only and versioned, with a hash of the notice text the member actually agreed to. You can show not just that somebody consented but what they were shown when they did.
Implied consent under CASL runs out. Sembr knows when a member's implied-consent window opened, counts from the qualifying event rather than from whenever anybody got round to importing them, and stops treating them as reachable when it expires.
When implied consent decays, Sembr writes a consent revocation, not a suppression. Those are different facts. The member did not ask you to stop; a legal window closed. Recording it as an unsubscribe would misrepresent them in your own records forever.
Suppression
A bounce, a complaint or an unsubscribe suppresses an address. A suppressed address is checked before every send, and a suppressed member is skipped and recorded as skipped, rather than silently dropped.
Suppression can also be platform-wide, for an address that has hard-bounced everywhere. That protects the sending reputation every organization on Sembr shares.
Sending
Build the campaign, then run a preflight. Preflight tells you who will receive it and who will not, before anything leaves. Read it.
Sends are paced rather than fired all at once, and Sembr will tell you honestly how long a large send will take before you commit to it. If a send would exceed what can go out today, it is scheduled across days and you are told which day each part goes.
You can stop a campaign mid-send.
The one thing to remember
The member sees your organization, not Sembr. Replies reach you. If your campaign is wrong, it is your name on it, which is exactly why the guards above are not optional.