Using a Z3100 to profile other printers

I just reread the article on LuLa about how to use the Z3100 and APS to read targets printed on other printers, to come up with a profile for another printer (with the same paper, of course.)

At first thought, it seemed impossible to me, but then I read the article carefully and became convinced it would work. However, given my still shaky understanding of color management, I now am questioning the process again:

Say I give the electronic target file(s) to a buddy who prints them out with absolutely no color management on his Epson 3880, on, for example, Epson Premium Luster paper. The deficits in color are the result of his printer and inks, and the Epson paper.

I now feed his printed targets into my Z, and it scans the targets believing they were printed on my calibrated Z. When it reads each patch, doesn't it come up with a profile that will correct the differences based on how to fix the colors with the Z's inks and the Z's own inherent color response? If so, how would that profile work on my friend's Epson?