There are things you notice that can't just be "changed" right away. I won't mention it, but there are some things that just become instinctive to a player... which can't just be stopped on a whim. That's what I prefer to focus on. Also, while they may switch fighting styles your still likely to get at least one win from your observations. While it may not work forever... any advantage is an advantage.
Also, who's sending them in than, Jon? I can go do it if you want, just say the word.