I think a large part of the precautions is because it's hard to tell who's carrying the virus. Everyone's seen somebody who just coughs or sneezes openly. Over-reaction maybe, but nobody wants to catch it and nobody wants to be LIABLE either...
Whether it was a bit of "engineering" in an election year is intriguing, but it's basically world-wide & beyond that scope. All the losses being suffered should arrive at China's doorstep, but I wouldn't bet on it yet.