I am thinking of leaving signs in public restrooms that say: "If this restroom needs attention, please scan this code". The QR code would lead to meatspin. Just kidding. But honestly, I would be willing to bet that not many, and likely none at all, would get redeemed out of the general public. Now in an environment with a high concentration of tech skills (e.g. DefCon) I could see a serious percentage of interest getting redeemed.
I wouldn't think that too many in general meat space would get picked up, but would still be interesting to see the numbers. It'd be really cool to see what would happen if there was some sort of nation-wide effort to drop these addresses to see the differences between regions on usage! The data would be wonderful!