Same Account on Multiple Computers?

This might be a question for the Steam forums, but I'm trying here, too, just to cover my bases.

I recently logged in to my Steam account on a different computer, downloaded the game and proceeded to play it only to find that all my custom classes and career earnings were gone. Do these stats not sync with the cloud? This leads me to believe that these things are tracked locally and I could simply edit a file somewhere and give myself a million dollars and unlock all the custom classes. Is that true? Kind of disappointing.

http://forums.steampowered.com/forums/s ... ?t=1713008

Also:
Properties -> Updates -> Enable Steam Cloud...

Thanks, I had it off because it seems to like to think that all computers will be able to handle the same video/audio settings you use on one (at least for TF2).