"trusted" usb keyboard

I can connect usb keyboard via the dock, everything works fine, but I don’t like either of the available InputKeyboard policy options : “ask” quickly becomes annoying, “allow” - for obvious security reasons (usb thumbdrive pretending to be keyboard is game over). Is it possible to have policy=allow for usb keyboard based on some attribute (keyboard S/N or usb hub/dock id etc), and use “ask” for everything else? I understand that malicious usb device can send any S/N but they would need somehow to guess what S/N my policy is expecting (and bruteforce is not possible because I will notice unexpected policy ask popups), this is the risk I am ok with.