So, I just did an assassination mission where I had to kill 3 guys in under 5 minutes, all of them with big posses.  Since there was a time limit, I jumped on a horse and just killed everyone from horseback, without getting hit a single time.  At the time, I just assumed I was a fuckin badass, naturally.  Now I'm back in town, and since my wanted level is up, all the guards are attacking me upon sight, like they should be doing.  However, "attacking" in this sense refers to them pulling out their weapons and just continually circling me in their defensive stances and doing nothing else. 
 
So either I just broke the game or Ezio is truly the most awe-inspiring assassin ever.

The guards are just trying to act tough but are terrified of you. They're probably whispering "No, YOU go first" to each other.

All I know is this is now gonna be the easiest game I've ever beaten.

You just won the game.

Woohoo, game unbroken!  I managed to get a guard to attack me