So, saying that wizards have a slight problem with modern technology is alot like saying that someone's "a little bit pregnant". Bony Tony tried to use that to his advantage in Dead Beat, but failed to fully realize the arrogance of the man he was dealing with. But his attempt to safeguard his loot using not one, but two layers of mortal tech, drove the plot quite satisfyingly.
Thus, I've been playing with similar ideas for game plots--methods by which mortals can outfox wizards and other supernaturals by taking advantage of various mental and perceptual blind spots. However, it doesn't seem that I'm quite canny enough, so I'm throwing this out there to see if anyone else has any ideas.
Right now, the only thing that I've really been able to think of myself are
QR Codes; freely available for both generators and readers, convenient reading of one "out in the wild" as it were, requires a smartphone, something that would last for about, oh, five minutes in Dresden's presence.
Anyone got anything else to add to the pile?