In Flagstaff alone, if we assume that of the 53 percent of units, 10 percent respond another two times and if my math is right, then we probably will see an additional increase in population by somewhere in the 24 percentile range. Even if my math is wrong, we will see a significant increase in population that isn't warranted. Now multiply that by the current estimated US population of 308 million (www.census.gov/) and we could have around 60 million extra bodies that don't exist.
One more problem I've uncounted is that I have a post office box. If I didn't receive mail at my condo, how would I get counted? Would this become a person to person count? What if you couldn't reach my home because it's too remote, gated, or in some other way inaccessible?
I wonder if there are "other" confusions that the Census Bureau has not taken into account. Input is strongly encouraged.