The Balmoral Tartan is considered a "restricted" tartan because one must have permission to wear it from HM the Queen -- the tartan was designed for Queen Victoria & named after her Highland estate at Balmoral, Scotland.

Some clan tartans are restricted in the sense that one must have permission of the Chief and/or clan society before wearing them, and usually the Chief and/or society sells the material exclusively.

Cheers,

Todd