guerrilla proofreading

(動名詞/現在分詞) 在公共招牌或標誌上劃記以改正或指出文法謬誤或打字錯誤。
guerrilla proofreader (名詞):在公共招牌或標誌上劃記以改正或指出文法謬誤或打字錯誤的人。

Guerrilla proofreading does seem to be a popular hobby for some people. They can get quite agitated about apostroflies, invisible hyphens, and other such entities.
—Stan Carey, “Grammar to go” (comment), Sentence First, March 26, 2010

On Wednesday, October 13, at the Decatur Library, writers Jeff Deck and Benjamin Herson will sign their new memoir The Great Typo Hunt: Two Friends Changing the World, One Correction at a Time. It's an English-action-packed memoir of public guerrilla proofreading that ultimately brought the authors in conflict against a misspeller with power: the U.S. federal government.
—Blue Elephant Book Shop, “Jeff Deck & Benjamin Herson sign 'The Great Typo Hunt' — Wed 10/13,” Facebook, October 7, 2010