I think this is not reason for ban, but everything happens, so you better email Google team about click bombs.
Are clickbombs where you suddenly have a suspicious increase in adsense clicks? If so, that happened to me over the weekend & I've just contacted google about it
First of all, clickbombs on referrals wont effect your account for the simple reason: 1) Referrals dont pay based on clicks, its not CPC, its CPA. 2) Unless the user takes action (signup, sale etc), the money is not credited to you.
god is right.. he beat me to it by this much... they can click on your referrals all day.. nobody cares..