So it's connector-specific? In other words, if I have a USB cable with USB-A on one and and USB-C on the other, the USB-A connector will be the thing introducing RF interference?
No. There's a long list of steps that a designer can take to eliminate EMI.
Things like good shielding, appropriate PCB design, differential cable drivers, and common-mode chokes.
If it were a good design, it would work satisfactorily with generic cables and connectors. And if it does require specific connectors (etc) it should not have removable cables.
Not necessarily, but it's slightly easier to make properly shielded USB-C connectors than it is for USB-A. I'm sure plenty of manufacturers will screw it up.
