Warranty and resetting Touch from jailbreak

If you click the Reset button (or Revert, I can't remembmer the name) in iTunes it removes and resets everything on your iPod Touch would that remove jailbreak too?

If the answer to the above is yes would Apple know you have invalidated the warranty should something go wrong?

These are hypothetical questions, obviously.

If you flash your device to factory settings, there's no way to know what was on it before. You're basically doing a format and reinstall.

I did this with one of my cell phones I hacked several times and had to get replaced due to an unrelated fault; replacement on warranty wasn't a problem.