pornocook uses iframe to install trojans. He's smart and not easy to catch - he seems to do not install it on every referrer and country, he uses some rules.
As for the rest, I must say that you should use more advanced scripts. I use free script Avrora, which is far not perfect, but has bult-in "no-cookie/no JS" protection and those traders you mentioned (I traded with some of them like 90-60-90 and some others) never showed more than 80% productivity, they died and I eventually deleted them, without even knowing they are cheaters.
|