I was saying that the existence of the non-implementation of USB proves the possibility of access controls on USB. Convoluted way to put it I guess. For some

I was saying that the existence of the non-implementation of USB proves the possibility of access controls on USB. Convoluted way to put it I guess. For some reason was intuitive to me (proof of existence by example, more trivial example better). Having access controls on USB-HID is just a local policy choice where most people would choose convenience over security.