But if they've studied the situation and have an incling of the incubation period they could pre-mail the second batch (that's what I was trying to get at but didn't do a good job as you can see). Also there's the possibility of the two waves not being related, of idiots (similar to the ones that were calling in al those bomb threats the week of the attack) mailing talcum powder to local (for them) places, that would give that next day thing, especially if your sending to big places that get multiple deliveries.
One of the dangers with this one, especially something this low rent to fake, is assuming it's all coming from the same source. There are way too many idiots in this country to assume no one has gotten the bright idea to copy these "attacks" with harmless powder. This is something almost every household in the country could fake, just need some sort of white powder and envelop and a stamp and you're ready to rock.
perhaps you misunderstood me...the quickness of which I was referring to was the idea that Tuesdays mailings were "Hoax copycats" and that was the impossibility I was referring to. Anyone who received a white powder on Tuesday would almost have to expect that it came from the same group as the anthrax. The white powder didnt become public until late Monday. Anything after this could be copycats or the like...and I think the terrorists would be counting on that.