You would never know it from the LA Times' story about the event: http://www.latimes.com/politics/la-me-ln-hillary-clinton-rally-20160505-story.html
They wrote: "A handful of Sanders supporters unsuccessfully tried to interrupt her evening speech, and scores more protested outside."
A score is 20, so "scores more" means some multiple of twenty. Many people don't even know what a "score" is; the only time we have heard it at the beginning of the Gettysburg Address: "four score and seven years ago...", meaning "87 years ago."
Other outlets at covered the protests, at least offering photos so some of the signs could be read. http://abcnews.go.com/Politics/hillary-clintons-cinco-de-mayo-la-rally-festive/story?id=38917455 http://www.dailynews.com/government-and-politics/20160505/live-coverage-of-hillary-clintons-rally-at-east-los-angeles-college http://photos.dailynews.com/2016/05/photos-hillary-clinton-campaign-rally-at-east-los-angeles-college-2/#7 http://photos.dailynews.com/2016/05/photos-hillary-clinton-campaign-rally-at-east-los-angeles-college-2/#38
Some outlets said these were "Sanders supporters", but the protests were organized by Union del Barrio, which has not supported any political candidate in the race.
There were Sanders supporters, but not all the protesters were Sanders supporters. The media could have learned this if they had read the protest event information online.
Fusion had a good overview of the protest. They covered a broad sentiment that Clinton was "Hispandering" by having her event in East LA on Cinco de Mayo, as well as some major issues raised on the signs: deportations of Central American children and the murder of Berta Caceres and Clinton's support of the coup in Honduras. http://fusion.net/story/299564/hillary-clinton-accused-pandering-cinco-mayo-eastla/
The Daily News, a slightly more conservative competitor to the LA Times, correctly stated that the Union del Barrio does not support any candidate.
This is important, because the Los Angeles left is diverse, and there is no unanimity that Sanders is addressing Latino issues adequately. Specifically, the UDB are interested in seeing the US pull back or end its right-wing, capitalist foreign policy.
The Daily News also described the Clinton fundraising effort in detail. Traditionally, politicians use Los Angeles as a source of funding, but not necessarily a place to fight for votes. For this election, both matter. http://www.dailynews.com/government-and-politics/20160505/hillary-clinton-to-speak-at-east-los-angeles-college-amid-protest
KABC 7 gave exposure to the protests on television. http://abc7.com/politics/hillary-clinton-speaks-at-east-la-college-amid-protests/1325047/