AC:B Minimal Kill Competition
...might as well start talking about it now!
(Warning: spoilers for the first and second memories of the game. Nothing you don't know about if you've watched the trailers and preview videos, though.)
The game arrived and what could I do but open it? 
In the very first scene, the game throws climbing, brushing past people, rooftop running, and then real combat right at you -- that last part being a few dozen guards chasing you and Mario as you try to escape!
I was able to use only my fists, throwing enemies around and letting Mario kill as he liked. Lots of grabbing and punching, but no blades, and I finished this section with 0 kills.
Then Ezio and Mario ride back home to Monteriggioni, and (I won't say how) you've got a big fight on your hands the next morning. This time, for some reason, the grabbing-and-throwing wasn't working -- I had 9 kills before I even knew what was going on! Still trying not to kill, I ended up dead myself, so I'll be restarting from that point tomorrow.
Has anyone managed to not kill anyone there? Has the game decided that people you punch out are now "dead"? Or should I just be more careful about how I dispatch them?