Imagine this... your website runs a CMS, part of the package includes "SEO", as you cannot control the FTP as it's the software providers code, you do not have access... They do.
They control the code/ftp therefore, they control Webmaster Tools.
The minute you leave, they go into Webmaster Tools and execute a site exclusion.
When I looked at the site yesterday and did a site: command it fetched 0 results.
When the company was approached, they said this was standard practice, leave and we exclude...
The good news, 14 hours later and they are back in the index minus any PR.
Surely, by you maliciously doing this , it opens up many questions including legal ramifications due to lost business? Luckily we restored things quickly.
Just shocked that people can do this...