In 2015's "Straight Outta Compton," there is a shot of a red/blue bandanna tied together following the killing of Rodney King, symbolizing the Bloods & Crips in unison. Was this actually the case or was it simply dramatized for the biopic?

This was actually the case, multiple times. But I feel the need to point out that the Bloods and Crips have many sects within them, and even subsects within those.

So, just because you see members of the gangs trading flags, doesn't mean every sect/subsect agrees. For example, let's just say every single set on the west coast agreed to a truce among Bs and Cs, it doesn't mean the Bs and Cs on the east coast are going to follow it. This is the same on the West Coast. If a Blood set from neighborhood A agrees to a truce with Crip set from neighborhood A, it doesn't mean the Bs from neighborhood A have a truce with Cs in neighborhood B. Same goes with the Cs from neighborhood A.

After the Rodney King beating, two sets of the Cs (The Grape Street and P Jay Watts Crips) and a set of Bs (Bounty Hunter Bloods) met in a gym to negotiate a peace. The truce resulted in a pretty decent sized decrease in gang violence for awhile, and the gang violence, especially killing is still much lower than since before the truce.

Here is an article from that time http://articles.latimes.com/1992-05-21/news/mn-325_1_gang-truce

http://thesource.com/2015/04/28/today-in-hip-hop-history-the-historic-truce-between-the-bloods-and-crips-in-l-a-1992/

http://www.scpr.org/news/2012/04/28/32221/forget-la-riots-1992-gang-truce-was-big-news/

Also, kind of off-topic, but the truce wasn't just because of the Rodney King beating. Outside of the history on minority relations with authority in this country, there was a girl named Latasha who got shot and killed in a Korean store over some juice that also set tensions in L.A. high. This is why Korea town was such a target during the riots.

http://www.southcentralhistory.com/la-riots.php

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