I do not believe that there is a way to not-require email at this time, or at least in a way which does not require modding the core files.
To prevent emails from being sent you would have to break PHP mail for the server, and then either not set up an email, or setup rules on the mail server to accept the email and then delete it (ie not route it to its destination), or block the web server from talking to the mail server thats configured.