Google Webmaster Help thread has an interesting question, does Google use QR codes for discovering new content and pages? Can GoogleBot read QR codes and follow through to the data, URL or whatever behind them.
Google's John Mueller didn't really know, he responded in the thread:
"That's an interesting question -- do you have an example of one that we could look at?"
I assume it is easy enough to test. Create a page somewhere, only link to it with a QR code. Make sure Google finds the page with the QR code and wait and see if Google discovers the page. Of course, you need to make sure Google doesn't discover the page other ways.
I am not sure why it matters to much.
I assume even if GoogleBot does discover pages through QR codes, which I doubt. That the QR code won't pass PageRank and necessarily past trust. But again, that somewhat can be tested.