>> High-ranking execs and employees change jobs all the time for numerous reasons.

They don't, that's why people are reading into it.

They really don't. What you just wrote is like saying "This is nothing out of the unusual. Cows turn themselves inside out all the time"

(http://www.southparkstudios.com/clips/149573/inside-out-cows)

They really do. Anybody who's been at a big company sees it all the time. Most don't make news stories because they aren't at a sexy company like Google, leading up a division that's well-known among consumers.

You wouldn't hear about something like the head of fraud detection at American Express leaving his job. I've seen it before (not at Amex, but other large companies).

That's only because you don't read creditnews.com.

When a major exec leaves in my industry, everyone is talking about it on Monday, and lawsuits often ensue if they end up at a competitor.

non-competes are void in California.

Not based necessarily on a non-compete, but based on similar and concurrent projects, "trade secrets" and "proprietary architectures."

only up to a certain seniority level

[citation needed]

There are things execs do that line employees don't that can presumably make a CA noncompete binding, like, for instance, accepting significant consideration specifically in return for a noncompete. But I don't believe seniority is itself a factor that can make a noncompete binding.