I've shot FT on and off since 1988. I've never knowingly hit the kz and not seen the target fall. On one occasion I placed an apparent hit in the centre of the kz with my first shot on a course and it didn't fall. I called a cease fire, went out and there was a tiny silver streak on the edge of the faceplace at 6 o'clock; I was wrong.
I've definately had at least 1 target fall in response to a miss. I have no plans to ever call a target again.