I use xmodmap to blow away any concept of "caps lock", instead using the
physical piece of plastic as a much more useful extra modifier key for
my window manager.

It would be nice if qemu would realise this and not go randomly altering
the capslock state of the emulated keyboard. I appreciate this will
result in not having an ability to set caps lock on the emulated guest,
but I'm prepared to accept that as My Problem. Getting it stuck in the
wrong state so everything I type has inverted capitals is not useful.