So setting it to line in mode by default would be safer, and only switch it to USB mode once something's negotiated a USB connection, but I can't imagine many early adopters being happy waiting 2 months for a working USB connection. And wiring it up in a way that allows it to accept USB noise and analogue noise at the same time means my idea of blankly switching the lines wouldn't work, but there's probably a way to do it, but my electronic knowledge doesn't proceed that fair I'm afraid.