I'd like to disable all email from being sent on our dev server even if server and credentials are used in the cfmail tag. I'd like the messages to go into the spool as undeliverable so that we can read them. 

This is on windows.

EDIT - why?
We currently have the mail server set as a dummy in the admin, but we specify a number of servers on various mail tags. Having been burnt once by a developer sending mail accidentally, we'd like to disable it entirely.