Is is possible to post the adsense script on 2-3 websites while we only register 1 with google? Because.. lets say my unregistered website has more traffic than the registered one.. how do they know that this is not illegal clicks or illegal impressions? Do they only check on the registered website or they know where u put your script at even though you did not register the website?
You can use your code on all your sites. Each banner will have your id in it, so they can track any clicks.
well, if you registered that site you are supposed to put your banners on it. Why did you even register it if you aren't going to use it? Anyway, it doesn't matter what site you use, you can put the code on any site you own.