I worked for a well known computer software company, and one of the close by teams worked on a photo-sharing web-app, which also allowed for private albums.
While analyzing the metadata someone discovered that a certain rare and expensive camera model was used almost exclusively to shoot models, including nude ones. Searching the storage for pictures made with that camera model became a popular activity in that team :)
So it's pretty easy to trivialize privacy breaches and rationalize it as "no harm was done"
What kind of guard will let a cube not pass through the system like that? If I were that guard I would find that cube throw highly suspicious.
And while we are at it, wouldn't it be easier to hide the microSD card under the tongue for example?
And lastly, where exactly are you supposed to stick that card into in the facility? Even low-level security companies glue all USB/card reader inputs.