Attach Video

Attach one of the caller's tracked videos to this placement.

This is where two visibility rules meet. A tracked video is shared with a workspace only when its owner opts in; a campaign is the team's by construction. Attaching therefore stamps the video with the campaign's workspace — otherwise a teammate would see the spend but not the video it bought, and the page would be arithmetic they could not check.

shared_with_workspace in the response reports whether that just happened, so the client can warn BEFORE the click rather than apologise after.