Legal Question in Traffic Law in Georgia

It's possible because she chose to drive in another state, which makes her subject to that state's laws, without abiding by them.

(A note: online "cards" do not comply with the law in many states. Why didn't she print out a paper one, which every insurer recommends people do?)

Here is the advice that one of the nation's two biggest insurers puts on their website: "The best way to show proof of insurance is with your insurance card. In case of an accident, make sure your insurance card is easily accessible so you can quickly exchange information with any other driver (or drivers) that may have been involved. Consider keeping a copy in your wallet and another copy in your car, so wherever life takes you, you'll always have access to it." Most insurers give similar advice.