What I received in my inbox last night:

Hello Ray Booysen,

It has come to our attention that invalid clicks have been generated on
the Google ads on your site(s). We have therefore disabled your Google
AdSense account. Please understand that this step was taken in an
effort to protect the interest of the AdWords advertisers.

A publisher's site may not have invalid clicks on any ad(s), including
but not limited to clicks generated by:

- a publisher on his own web pages
- a publisher encouraging others to click on his ads
- automated clicking programs or any other deceptive software
- a publisher altering any portion of the ad code or changing the
layout, behavior, targeting, or delivery of ads for any reason

Practices such as these are in violation of the Google AdSense Terms
and Conditions and programme polices, which can be viewed at:

https://www.google.com/adsense/localized-terms?hl=en_GB
https://www.google.com/adsense/policies?hl=en_GB

Publishers disabled for invalid click activity are not allowed further
participation in AdSense and do not receive any further payment. The
earnings on your account will be properly returned to the affected
advertisers.

Sincerely,

The Google AdSense Team