The only thing I remember causing a failed USB port in the last 600 or so systems we've built was someone stepping on the connector on a front mounted port. So far it has not caused any damage beyond a failed port. I've had 2 systems at one customer have that happen, and I warned them in advance about the position of the system. Had to cut the cable internally to one port only because it continually caused the OS to pop-up that there was something incorrectly inserted in the port.