Are you still sure?
I did read that, in fact. But it turns out there's something even more important that we both failed to read:
The original attack description
As I suggested, someone more skilled in batch found a better way to hide it. It turns out there's no need for folding, escaped backslashes or any of that. All you need is the & sign.
FN:John Doe & msg * Hacked
So there you have it. And please, if you're going to claim this is also invalid vcard format and "trivially discovered", explain why and how this time.