If you're attempting a QR Code campaign, WAIT! Call me and I can help you avoid making this sort of disastrous mistake.
Dotted all around Southeastern's train carriages are posters like these.
A fairly small QR code, with a reasonable call to action. Not the best use of QR codes - but fairly inoffensive.
But what happens when we scan it?
An error page. To make matters worse, it's not even a mobile friendly error page.
We've known since the late 20th Century that webmasters shouldn't break their sites when they redesign them. There is simply no excuse for this. You don't simply 404 old pages when you shuffle around your website - especially if you have publicly printed the URL all over the place.