This is very interesting.
I think she left the country, btw.
Technically, “stealing” (it has to be like this, I can imagine tossing my purse, zip open, somewhere on a sofa. Not my responsibility that something has disappeared).
What document is easier to steal/use?
I wonder if it was enhanced driver’s license if…if Christine did not return the old, un-enhanced driver’s license to the Department of Licensing. Could it happen? Theoretically, yes, and even unintentionally. TBH, photos on drivers licenses are far from Annie Leibovitz’ creations, so crossing a border with one of them is not hard.
The problem falls on Christine as she has to get a new one, but I can think of certain scenarios when for some reason, while exchanging a regular license for an enhanced one, she could have kept the old one. (Or: lost an old one. Honestly. Reported, got another one, then, found an old one.) So she can use it for a few days and later, just report lost/stolen license.
This is easier. Passport is a more serious document, but after all, the sisters do look similar, and might be even more similar with the same hair color and style.
Passport in many ways is more convenient as Christine may not notice its disappearance till she decides to travel, and it might be in a year.