I hate to admit it, but you have to give credit where it is due. I have been following just one keyword but it may apply to others. Google has only charged me for one click in the past 7 days when the suspicious clicks for that keyword are at least 10 to 15.
I think I know what click behaviour is ignored by the Adwords software (i.e. not charged to the advertiser) but I am not going to spell it out here.