You can block a SmartFrame on a specific URL at any time. The SmartFrame in question will no longer be visible on that URL, although other SmartFrames on the same URL will not be affected. If you want to disable all embeds on a specific domain, you can blacklist the domain in the Control section of the Admin Panel.
To block an individual SmartFrame, you can either select it in the Embed report or go directly to the Embed page by clicking on the embed in the report and clicking the Block button, before confirming your decision. Once a SmartFrame is blocked, it will no longer be visible on this specific URL and will be replaced by this image:
You can unblock the embed at any time by clicking on the Unblock button.