By default, swap request notification emails will only be sent to volunteers who have the services for which the swap is being requested as a preference (and who do not have a can't serve time at the time of the service). However, you can override this behavior so that all volunteers in the ministry will receive the swap request notification email, regardless of their service preferences and can't serve times.
You can do this by going to the Web Terminal pane on the left side on the left side of the program window, clicking the My Schedule tab at the top, and then clicking the "Token Options" button at the top of this screen.
In the Token Options dialog, for the "Swap requested positions options," uncheck the option that says "Include only positions at services at which this minister can serve".
Turning off that option will ensure that swap requests are shown to everybody in the ministry, even if they are for services that are not the minister's normal preferences. It will also ensure that swap request emails (if turned on) are sent to everybody in the ministry, regardless of their service preferences and can't serve dates.