It might just be partially in the nature of the culture; I've seen it happen a million times. T10 typhoon incoming? Better hope you have rice at home, because shelves will be empty. Fukushima blows up? Somehow people thought eating lots of non-iodized salt would help, so no salt on shelves for a week. Even when the protests started, people panicked and started stocking up. I guess they thought there was a chance China would come in with tanks and lock everyone in their homes.
Actually I can't really remember what it was like during SARS though. To my recollection it wasn't that bad. A lot of people wore masks, but NOTHING like today. So maybe the panic thing is a more recent thing, as people learn that their government is absolutely useless. All they do is protect the CCP and the Police.
I didn't ever wear a mask during SARS, and I hung out at Amoy all the time (
bad idea in retrospect). One day I was there, and all the stores were closed and dudes in full body suits were wandering around... I guess that was the day they discovered the cause
