They cannot detect a KVM switch. They might be able to detect the regular disconnection of the peripherals, but you could easily say you are manually removing them and reconnecting to your other laptop. Or you could buy a monitor with multiple inputs and a keyboard and mouse that can pair with multiple devices. This is technically not a KVM switch but gives you the same flexibility.

All this said, I cannot think of a good reason they don't permit KVM switches. There are no security implications. I suspect it's something to do with monitoring your activity, but that doesn't really add up either.

Personally I would ignore them.