Not many lawyers here on El Reg
I think we're all in for a bad time if the police are allowed to make up the law on the go, whether or not we think it was a good idea. If this goes to court, the citation will most likely be struck down. Here's why:
Section 27602(a) contains the words 'is operating'. That is to say that it is illegal to drive a vehicle while a display (excepting those listed in 27602(b)) is switched on. As the lady swears it was not switched on, and assuming the cop had not checked it was by removing the glasses from the lady and looking into them himself, she cannot be said to have been driving while the display was "operating and ... visible to the driver" (as specified). The arresting officer would be asked how he could ticket a driver for using an operating display when that display was not operating.
Interestingly, 27602(a) seemingly also makes it illegal to use a smart phone as a sat nav in California. Why? Well, you can also watch video on a smart phone, and so it would not be exempt, as it neither satisfies 27602(b)(5)(A) – it would have no interlock to prevent the driver from watching video – nor possibly 27602(b)(5)(B) which states that the smartphone must be "designed, operated, and configured in a manner that prevents the driver of the motor vehicle from viewing the television broadcast or video signal while operating the vehicle in a safe and reasonable manner". While a smartphone can be configured and operated in this way (and I guess Google Glass can too), I know of no smartphone which is *designed* in such a manner.
Of course, I am sure that the smartphone makers – and everyone else – would argue that watching video while driving would mean that you were not operating the vehicle in a safe and reasonable manner, and that to be safe and reasonable you would have to not be watching video. That, of course, would be a legal catch-all, meaning that, as long as whatever display you were using was set up as a sat-nav, you could legally use it and that would include Google Glass.
Damn it, I should have gone into law, rather than music.