Hey Brian. I have been through this many times before - there is no simple way to turn off all outgoing emails through some system property or admin console setting. We always end up deleting the email config options in test/ UAT situations.
Should you want the system to have default settings that are different than out of the box (to turn off digest emails for instance , without effecting other settings or the ability to send emails in general), there are some undocumented system properties that may help you : Undocumented Jive System Properties
These settings only affect users that have not set their personal email preferences.
Thanks John, this is for the Pilot system that is still on but not being used until we get the Production system online. Some people don't want to get stale emails from the Pilot system. I'll look to delete the email settings for that system for now.