Was your friend's office for Amazon, or a subsidiary? According to the NY Times:
"The law had said that an online retailer needed to collect taxes on purchases if it had a physical presence, or a nexus, in a particular state. Any retailer with an office or warehouse qualified. Amazon had no such facility in California."
If your friend turned down a job at an Amazon office in California then Amazon should have been charging sales tax in California BEFORE the law was passed. I have a feeling that your friend was offered something else:
"California’s new law goes further by including related companies, or subsidiaries in its definition of a nexus. Several Amazon subsidiaries have offices in California like A9, which works on search technology, and Lab126, which designs Kindle digital book readers."
There are no Amazon offices in California:
http://www.amazon.com/Locations-Care...node=239366011
Plus, if you go to the jobs section and perform a search for all of California, all jobs are listed in Cupertino, CA... for the aforementioned Lab126 company.