I know there is no Adsense on that site. Justed wanted to point out that it's the kind of site (only search results and ads) that Google is likely to ban from the Adsense program. If your friend has a site like that (I am not saying he has) there could be other/more reasons for Google to ban his account. However, the ban occurring right after (either insane or revengeful) coworkers were clicking all over the site should be more than a coincidence.
Whatever the reason of the ban, Google included in their TOS an option to ban any site or account whenever they feel like it.
The injustice of that has been discussed here many times.
I don't think Google cares one bit about that.
[edited by: BrandNewDay at 10:15 am (utc) on May 23, 2008]