Bill Wright explained on 15/07/2018 :
A flat plate on one site of the tx will not prevent transmission.

I wasn't suggesting it would. My wallet is a back pocket folder, the
height of notes, but when the wallet is folded the notes are folded, as
is the foil. The foil is the full size of my wallet when open and
inserted in the outer note compartment.

Folded and in my pocket, my cards are tightly sandwiched on both sides
by foil. Does that explain it better?