A man from Somerville, Mass., and his friend who went around the country this year removing typographical errors from public signs have been banned from national parks after vandalizing a historic marker at the Grand Canyon.

See also coverage at the Times UK, from which the title is taken:

The founders of the Typo Eradication Advancement League (TEAL) have been banned by a court from correcting any publicly owned signs after trying to correct one on the Desert View Watchtower that, for seven decades, has drawn attention to an “emense westward view of the Grand Canyon”. Oblivious to grammar, the prosecutors pronounced the sign “a unique historical object of irreplaceable value”.

Also worth a "look" -- The “Blog” of “Unnecessary” Quotation Marks, which has been misinterpreting bad punctuation since 2005.

Vigilantes wage war on signs of American illiteracy