I am very concerned to my friend that get banned by Google though he have two year associate with Google Adsense.

Just to the point (his name and his site will not published), that he give some advice to keep active your GA account :

• If you’re using internet on office/corporate area, just create one GA account (corporate account). Don’t there’s others signup in the same corporate/office
• Don’t signin to your GA account with IP shared connection. Others one person get banned, you’ll get banned too
• Have an access the internet that using by together, avoid to make the GA account or login from there

Just sharing, hopefully this useful!.