> Maybe she thought physical paper would be safer from digital surveillance than an email. So she printed the documents at her office [my emphasis] and then mailed them
You can't just plug in a USB key a copy it off. If she'd been randomly searched when leaving, then accidentally removing a printout (with a bunch of other doc's) would earn a breach and possibly loss of access, but it isn't as incriminating as a USB or camera.
> Maybe she thought physical paper would be safer from digital surveillance than an email. So she printed the documents at her office [my emphasis] and then mailed them