Its tongue in cheek to an extent. But an element of truth there. Ive been told that beer will ferment with one cell. The trouble is that something else may take hold while you wait for that ~90min doubling rate to go from 1 cell to 1,000,000,000 cells. So if I get ~100 billion from wyeast and get them fired up in a liter, and pitch while they have their thing fired up, I figure in fairly short time they will figure out how many troops they need to do the job. Rather than trying to start with the right amount when I don't know how many I actually have... I let them do the counting.