basically... this traffic is not really his...
so he wants to monetize it... whatever way..
but not so that people notice a change on the website...
that is what is sounds to me...
Maybe someone wanna buy huge amounts of iframe traffic..?
I would just drop 100 relevant cookies per visitor, thus dropping 50000000 cookies. I do this on three days making the drop look like a huge advertising campaign.
At 1 percent conversion on your visitors, at a .5 percent conversion that's 250,000 sales.
Just dropping amazon would result in a load of money.
However you have to be creative and smart to get away with it and most importantly be paid.