I fail to see how this will cripple our infrastructure as there are always alternate roads and it takes about a day to clear and lay down a significant amount of asphalt
Taking out bridges again just screws local trafic.
It's also easy to infect yourself in this setting. Plus, no one is going to notice the new guy bringing vials of clear or cloudy liquid he likes to pour on the infidels cheeseburgers?
those packages are checked for this sort of thing, if anything slips through it'll just insure better checks.
Infrastructure?
Like to see them try, most of our 'top' government and financial buildings aren't well known and are spread across this beutiful country of ours. They'd need an army.
Some guy already tried to do this here. At least here in chicago it's kind of hard to move around the subway if you don't belong there, Again how do you prevent poisoning yourself in this setting. And anyway with the constant excange of air and the seperate lines this guy'd have to have gallons of the stuff and ride the subway for a year just to get to every line.
How they get to be rail mecca? Well chicago's no slouch. Lot's of trains here, I find it hard to belive that you're going to be able to do what it takes to stop a train and get away, drive across town to do it again without a, getting killed and or recored in the act, and b, noticed by the cops.
Now this has a chance of actually happening. But happening on a scale that could threaten our infrastructure? No.
The country is simply too big for any attacks from these guys to have more than a symbolic effect.