There's now a layer of corporate muscle standing between window-smashers and Google's soft, fleshy staffers: Reuters reports San Francisco's highly controversial campus shuttles are now being guarded.

On two successive days this week, a pair of young men stood on a San Francisco street waiting for the special "Gbus" that ferries Google staffers to the Internet company's Mountain View headquarters 34 miles to the South.

Dressed casually in jeans and wearing black ski hats or hoods, the two men did not stand out from the dozens of other young tech workers waiting for the Google bus. On close inspection, each sported the curly wire of an earpiece, and one occasionally jotted notes down on a yellow stick-it pad.

If Google would put face computers on these guys, it would really help quicken the inevitable descent into sci-fi movie turf, but no dice for now.

If you see some Silicon Valley sentinels, snap a pic and send it to me.