You misunderstand Steve.
A sledge hammer will bounce off causing no damage. The CFRP is THAT strong! In fact the traditional 'cut here' red markings are useless if you want to get in with an axe. Fire services will have to use cutting blades such as rotary saws to get through the skin.
I also understand that the traditional cockpit axe is not fitted either as it's next to useless on a 787.
It takes something heavy with momentum to actually cause serious damage.
IE. Catering truck or hi-loader.