So maybe they're both bad ideas, I can accept that. In fact I know I personally would be far more likely to just Google "budweiser superbowl" than pay attention to the URL, but if I'm going to pick one or the other for my ad I'd stick with a URL. Those same people you reference certainly aren't the ones who are going to both know what a QR code is and have the motivation to scan the code. Anyone could read a url and remember it whereas no one I've heard of can look at a QR code and understand a lick of it. If nothing else I stand by a URL in this situation being a better bad idea than a QR code.