Ah the joys of working for a university. So many bright, young and enquiring minds, and those days seemingly all equipped with an iPhone.
So I guess it was only a matter of time that some of them would think of using Cardstar, an iPhone app for managing barcoded cards like supermarket loyalty cards, to keep a copy of their library card barcode and turn up at the issue desk presenting their iPhone to be scanned.
Of course, the devious could have easily added their girl/boyfriend's card to the collection as well, not to mention the barcodes of their last two ex-g/bf's in order to ensure that they get all the relevant books for that term paper. (And indeed for the malicious aor devious run up fines on the ex-g/bf's account or hog books to stop others using them - libraries - all human life is there)
This isn't an problem per se for manual book checkouts - issue desk staff can either demand to see supporting id eg driver's licence or indeed if they don't have their official card tell them to bugger off (in the nicest possible way, of course).
But of course we are all high tech and have automatic checkout machines which work by scanning the item barcode and the library card which are placed together in the scan zone, meaning it would be quite easy to take books out under someone else's barcode.
Fortunately, more by accident and design, the book issuing terminals seem not to cope with scanning iphones and fail to issue a book nine times out of ten.
This doesn't mean that it isn't a problem, just that we've got a little time to come up with a solution.