Yes, the media jumps to conclusions. Sometimes it's reasonable, but there's a line between cautious and crazy paranoid. We all should be vigilant, but you can't be suspicious of everyone who looks or acts different. In this case, it was an active shooter drill. Since it happened so soon after the attack in Istanbul, I get that people thought it was a real event, and that the media broadcasted that.
Yes, the media jump to conclusions. It is a function of the way our media is set up. Media is all immediate now. Readers and viewers demand instant information and individual media outlets have to compete to be the first to give the news. This is one sad part of the decline in newspapers. In a newspaper there is more time to get the facts right and to do an indepth, accurate story.
Because US media would rather tell us "Stories" and "News" stories about garbage rather than report actual, factual news. Just glad we have other sources that we can rely on while US media focuses on what new dish you can cook and bring to the table or the ongoing (yawn) Hillary and Trump fuss fight ...
I think the media often does jump to conclusions. There is so much competition between different networks and media outlets to be the first to report a story. With all of this competition, sometimes false media is reported in order to ensure that if a story exists, one network or outlet has it first before the others.