in tkd, it'd not have been awarded points if kick was unintentional but landed on his head/face.
but the main point is why din opponent block the legs instead of hands wide-opened,
or launch offensive moves like punches before his face/head was landed with the 'butterfly' kick . . . . ?
similarly in karate, opponent's punches may be damageless or simply 'action only', but as long as it landed on its intention target(s), point(s) are awarded
and there are always occasions where competitors win not becoz he/she was good but rather his/her opponent broke the rules and lost by points
so, these are considered as "sports", and not contact martial arts like mma etc.