I have a Retina MacBook Pro, that connects to a wireless network at work for intra- and internet access. I also regularly plug in an ethernet cable to access the same network. In my Network preferences I've ordered the USB Ethernet connection above the Wi-Fi connection, so my computer should prefer the ethernet connection. However it still connects to the wireless network, burdening our wireless router for no reason.
How do I configure my Mac to automatically disconnect from the wireless network, when it's connected to the Internet over an ethernet connection?