I'd personally rather they developed a CCS adapter
Literally the title of this thread.
Have you looked at an actual CCS1 plug?
Not only have I, but I have a copy of the spec from CharIn. Which you should also go get a copy of.
Having the plug disconnected by a user in the middle of a 400V charge session would be dangerous because even the energy in the wires can hurt someone at that point.
That's the job of the pilot pin, which is what controls voltage flowing. Again, this is spelled out in the standard, which I strongly encourage you to read.