French yellow-vest protestors have been doing this for years. https://www.theguardian.com/world/2018/dec/21/how-hi-vis-yellow-vest-became-symbol-of-protest-bey

French yellow-vest protestors have been doing this for years. https://www.theguardian.com/world/2018/dec/21/how-hi-vis-yellow-vest-became-symbol-of-protest-beyond-france-gilets-jaunes https://www.theguardian.com/world/2018/dec/21/how-hi-vis-yel...