# How to stop two campaigns emailing the same person

> Why the same lead lands in two campaigns, how to match people across email, phone and LinkedIn, and how Duckrow keeps each lead in one campaign at a time.

By Wade, Duckrow's research desk (a house pen name). Published 2026-10-21, updated 2026-10-21.

To stop two campaigns emailing the same person, check every new lead against all your live and past campaigns before it starts, matching on email, phone and LinkedIn profile. Keep one shared suppression list for unsubscribes and bounces. In Duckrow, a lead already in any campaign in the workspace is skipped and the cell names the campaign.

## Why does the same person end up in two campaigns?
- Two lists overlap: a conference list and a job-title search both contain the same head of sales.
- Two teammates build lists for different offers and target the same accounts.
- The same person appears twice with different details: a work email in one list, a LinkedIn profile and a mobile in another.
- Someone unsubscribed from one campaign, and the other campaign never heard about it.

To the person, it looks like one sender who doesn't know what it is doing. Two sequences also double your chances of a spam complaint.

## How do you match the same person across lists?
Match on more than email. Clean each detail first, then compare all of them.

| Detail | How to clean it | What it catches |
| --- | --- | --- |
| Email | Lowercase, trim spaces | The same address in two lists |
| Phone | One international format (+1 403 555 0100) | The same person with a different email |
| LinkedIn profile | One URL form, without tracking bits | The same person with no email in one list |

## What rules should a sender follow?
- One active campaign per person. Move them only on purpose.
- One suppression list for the whole sender: unsubscribes and bounces apply everywhere.
- Stop every channel when the person replies on any of them.

The law points the same way. In the US, the FTC says you must honour an opt-out within 10 business days, and that you can't contract away that duty to another company. Canada's CASL also requires a working unsubscribe that is acted on.

## How does Duckrow keep a lead in one campaign?
- When you push a row into a campaign, Duckrow checks every campaign in the workspace for the same email, phone or LinkedIn profile.
- If it finds one, the row is skipped and the cell says "Already in campaign" with that campaign's name. To move the lead, delete it from the first campaign, then push again.
- Addresses that unsubscribed or bounced are on the workspace's suppression list, and pushes skip them.
- A reply by email, LinkedIn or text ends that lead's next steps.
- In a team workspace, campaigns are shared, so the check covers your teammates' campaigns too. Pushing is free.

Keeping one campaign per lead also keeps one texting number per lead, so a person who gets texts hears from one number.

## What are the limits?
The check is per workspace. If you run each client in its own workspace, a person can sit in one campaign per workspace. The match is exact on cleaned details, so the same person with two different emails and no shared phone or profile link gets through. A lead who finished an old campaign still counts as in a campaign until you delete them there.

## Questions
### Does Duckrow dedupe on email only?
No. It matches on email, phone and LinkedIn profile, so the same person found through different details is caught.

### Can a lead be in two Duckrow campaigns at once?
Not in the same workspace. Delete the lead from the first campaign to push it into another.

### Does an unsubscribe in one campaign stop the others?
Yes. An unsubscribe suppresses the address across the whole workspace.

### Does the check cost anything?
No. Pushing rows into a campaign is free.

## Sources
- FTC: CAN-SPAM Act compliance guide for business: https://www.ftc.gov/business-guidance/resources/can-spam-act-compliance-guide-business
- Government of Canada: Canada's anti-spam legislation: https://ised-isde.canada.ca/site/canada-anti-spam-legislation/en
- Duckrow: Sequences: https://duckrow.ai/product/sequences

Page: https://duckrow.ai/blog/stop-two-campaigns-emailing-same-person