Here's an article about the drill.
LinkQUOTE
Thousands of workers from four downtown high rises left their jobs early today, flooding the streets and testing Chicago's emergency response plan.
The city's first-ever mass evacuation drill got underway as planned about 4 p.m. Thursday afternoon. Roughly 5,000 volunteers took place, simulating a scenario where there has been a credible threat to the city and an evacuation has been ordered.
I note that these were volunteers, so I assume that nobody was forced to participate. However, obviously people had their workday commute disrupted by this exercise against their will.
I think it's important to use this kind of thing in order to be as prepared as is reasonably possible for emergencies. It's not a perfect simulation of the real thing, but it's a lot better than nothing.