Hiding through design! Just don't mess with them. Changing the appearance of QR codes is just one step from hiding them. I've done unformal UX tests and codes that don't immediately trigger "that's a QR code" simply don't get scanned.

This very much depends on which QR code library the user is using

Weird nothing was mentioned about bastardizing the finder patterns.

cool, but you are better off not reading any of these and just not doing wacky shit.

> There's redundant information so you can put your logo in the middle if it's just 30%.

And this has a green tickas if it's the things that you can do? Don't sacrifice data redundancy that may increase failure rates just so your thing can look cool.

And this is a general principle, if you are designing a website and you think of a cool thing that will increase coolness by 10x, but decrease the contrast of text and make it slightly harder to read by 1% of the population, don't do it.