Is using filter to ban G! a good idea (adwords, base.. )? (Even if recip not required, should it be expected then?)
I think you need to explain your question a bit better. As it is I can't understand what you are asking.
Yes, it is a good idea in my opinion to filter out URLs. A lot of sites will use eCPM ads which will really drive you barely an revenue while using real CPC ads will get you a lot more. I filter out around 60-80 URLs to clean up my CPC network ads.
Actually there isn't a thing such as eCPM ads. The two types of ads you get in AdSense are: CPC = Cost per click: You get paid each time someone clicks on the ad CPM = Cost per thousand: You get paid a certain amount for every 1000 impressions of the ad. So each time someone views the ad you get paid a very small amount. eCPM = Effective CPM: An indicator to show how much you will have earned for 1000 impressions. It is calculated by total earnings divided by the number of page impressions and then multiplied by 1000.