Switching jobs a problem?

Microsoft's argument in their legal case against former executive Kai-Fu Lee and Google has taken an interesting turn.

"The high-profile dispute largely hinges on a noncompete agreement Lee signed with Microsoft. But in court filings, the software giant has also mentioned the theory of "inevitable disclosure," which holds that in some circumstances people can't avoid sharing or relying on trade secrets from their former employer when moving to a competitor."

I wonder how far that can be pushed?