Do impressions with no clicks hurt overall earnings?

I am wondering about vbulletin board I run. Since guests or recently joined members are likely to click on ads I was thinking about making a conditional to not display adsense to team members(moderators etc.) who make a lot of pageviews but I am guessing are blind to adsense by now.
But I wanted to clear something first. Do these impressions made by them hurt overall earnings? Considering that ecpm is pretty low for those ads. I realize they decrease CTR, but does that effect cpc or ecpm?

 

Yes, low CTR can result in smart pricing. Display AdSense ads only to true members.

 

I think impression won't harm overall earnings.
forum usually low CTP due to old member visted.
i remeber google suggest forum ower should change ads color template frequently

 

I even believe that impression won't harm overall earnings.

 

Thanks for replies.
Well I'll try displaying them only to certain user groups for few days and see if it makes any difference.