I don't think there are many people using macros, most feints are just way to easy to block for what I imagine what a macro is. Also, I agree with Shema that you just have to try it out yourself and you can get some decent faints, maybe not the best, but they can work out.
Back again to the cheater topic: I have met a player once I suspect of cheating (won't tell his name). He was first of all blocking everything which isn't suspicious at all, considering how many good gamers
play Mount and Blade in general. What made me suspicious is that he chambered every hit and every faint, it did not matter how long I was holding my attack. One might say he is just pretty good, but tbh I have never seen such a skill like that and I played with many of the warband ludus duel pros (not saying it is impossible). Furthermore, I saw him some weeks before and after this duel and he was not able to block at all, neither he could chamber, feint or whatever. He was actually worse than the average player. Maybe he is just one of the most talented players in Mount and Blade who likes to hide his skill, but from what I ve seen I am convinced that he just tried out some cheat on eu3 and then uninstalled them again. That is why I think it could be possible that there are some cheaters. Nevertheless, it seems to be very unlikely to me that many actually do so.