> Our local libraries, The Seattle Public Library and the King County Library System, issue pieces of plastic with barcodes printed on the back assigned to your borrower account.

I just memorized my account number for KCLS. It should take maybe 30 seconds to commit it to memory—though your mileage may vary, I have to believe it's faster than this. After that, you just type in the account number instead of scanning the bar code, and probably do it in less time than it takes to get your phone ready. I don't know if SPL works the same way, as I'm not in Seattle.