Is there any word on whether the cables will be different? I suspect the cables will match, but the protocols the port support will be determined by the controller chipset.
I can't see how the cables will look much different between each other but even so they will all fit the same connector. There's already planned the 20gbps copper, 40gbps active copper and optical.
What mechanism can stop the £0.99 charge only cables people expect to plug in their portable hard drives through.
> What mechanism can stop the £0.99 charge only cables people expect to plug in their portable hard drives though.
This has nothing to do with this Thunderbolt announcement, the situation would be the same even if only USB 3.1 was supported. However, the solutions are the same as ever:
1. Don't use charge only cables, buy cables that support charging and data. They're normally affordable.
2. Keep the charge only cable plugged in to your power source.
3. Mark the charge only cables with a sticker.
As for the Thunderbolt 3 announcement, it looks like there are three proposed cables, and it looks very likely that the passive and active versions will support both USB 3.1 and Thunderbolt 3. Perhaps the light based ones won't, but they'll be niche at first, unless Thunderbolt 3 takes off rapidly.
USB-PD can check the cable to see what it's capabilities are so it won't push too much current over the wrong type of cable. I imagine any scheme to use TB3 over a Type-C connector will be able of checking the cable as well.