As a Lead Link or Administrator in your organization, you can assign people to roles and choose to "Exclude from Meetings". They will be a role filler as normal, but will not be included on the governance and tactical email outputs that GlassFrog sends at the close of a meeting. This is a useful way to enforce the "de minimis" provision in the Holacracy constitution.
The Exclude from Meetings checkbox appears on the role assignment dialogue, shown in the screenshot below:
You can tell that a user is excluded from meetings because they will not be listed as a "Core Circle Member" on the Members tab of the Circle Page: