Allowing Duplicate Leads in Smartlead Campaigns: Key Insights

For the smartlead action of Add Lead To Campaign, for this checkbox for allow duplicate leads across campaigns, if we run multiple different client campaigns on our smartlead account, I assume we should toggle this on to allow for duplicate leads across campaigns in case some of our clients are targeting the same leads. Meaning, there's no way to not allow duplicate leads across campaigns tied to a specific client right? I assume I'd need to make an API call for this and specify by client_id?