@Anomnomnomaly Hmm. While undoubtedly you have to be careful of QR codes (same as any links) your advice isn't quite right.
With a modicum of care and common sense, it's entirely possible to use QR codes successfully and safely.
A QR code pointing to a URL is effectively the same as a link, and you wouldn't say "Never click any links! Ever!!" now would you?
Yes, caution is needed (with anything online) but there's really no need for hysteria.