Restrictive signs sprang up across the southern and western landscape. They were constant and humiliating reminders with a common message—“stay in your place.”
From the Smithsonian National Museum of American History’s exhibit Separate is Not Equal: Brown v. Board of Education, 2004. Specifically they are from the Segregated America section:
"Restrictive Signs," in Teaching with Laurel Grove School, Item #43, http://chnm.gmu.edu/laurelgrove/items/show/43 (accessed December 12, 2013).