This is definitely an issue but I wonder how the average coin would fare against X-ray or even deep radar. I think a test is in order.
Place two QR codes at 90 degrees to each other to obfuscate each other if their is any penetration from xray or deep radar.
Also placing 4 small drops of superglue at the four opposite sides of the holo will create a challenge in peeling the holo without any damage for sure.