The phrase "black armbands" symbolizes mourning or grief in a simple and recognizable way. People wear black armbands to show sadness or respect for someone who has passed away or to express mourning for a tragic event. Full definition
«Ugo» was chanted by fans throughout Wembley during a minute's applause, with players wearing black armbands in memory of the popular former defender who died aged 44 on Friday. (espn.com)
Thomas would have overruled Tinker v. Des Moines Independent Community School District, a Vietnam - era (1969) case involving students who wore black armbands in protest of the war. (educationnext.org)
Most of the other kids didn't get me at all, with my dictionary vocabulary, spiral perm, green raincoat, tartan gym boots, red leather bow tie and black armband when Split Enz broke up. (housegoeshome.com)