In martial arts where striking is the order of the day, you prepare for that- you expect it. Let's take boxing for instance...as I have a long history of exposure to it; when I get in a ring, I know what to expect. Now, if you put a kickfighter in the ring with me, and I'm used to fighting by boxing rules, I'm going to be unprepared for a kick should he decide to throw one.
I was surprised to see that kick performed and landed; I guess because I was not prepared for something like that. I also cannot recall such a maneuver in the dozens of SCA vids I'd ever seen. I don't know much about BotN or its ruleset so my comment was strictly based on the video provided.