heres my take on the situation. In the Past 2 months, there have been a huge boom in cookie stuffing, I mean it went from barely finding anything on the subject , to full blown blog sites ect... Ebay had to know that there where massive amounts of people cookie stuffing. I sure there affiliate pay our went sky high recently....
Now most people who stuff, tried to stay under the radar. and ebay doesnt have the time to go and check every accounts traffic. So Lots people make 50 - 100 daily stuffing under the radar for the past few months.
Ebay needed to devise a way to catch all these under the radar stuffers. and they took examples of pure white hat site stats. Stats we wouldnt think of like, after a user clicks an affiliate link, how many times they revisit ebay ect.. and guess what bingo, the habits of someone who knowingly clicked an ebay ad link, are going to be different to the habits, of someone whos computer got stuffed and maybe doesnt even use ebay. Think of it say you stuffed 10k computers with your cookie, and maybe not even half even log onto ebay, thats alot different actions than if you got 10k real ebay users clicking on your affiliate link bringing them to a targeted item.....