> Presumably this is where the connection arcs every time it’s unplugged. I’m not sure how USB mitigates this, but it seems to be less of a problem. Maybe the contacts are simply thicker and more durable.
My guess is that it's probably just the good old "different length pins" trick. A quick web search shows me that the VBUS and GND pads (which carry the power) on the socket are longer, so the rest of the contacts unplug first. And unplugging the CC contact means that the pull-down resistor on it disappears, which tells the source to stop sending power to the VBUS contacts before they start to unplug.
My guess is that it's probably just the good old "different length pins" trick. A quick web search shows me that the VBUS and GND pads (which carry the power) on the socket are longer, so the rest of the contacts unplug first. And unplugging the CC contact means that the pull-down resistor on it disappears, which tells the source to stop sending power to the VBUS contacts before they start to unplug.