Yes. By default for all new Mobiniti users, we have the setting "new contacts" subscribers filter enabled automatically on all campaigns. This will ensure that if you schedule your campaign today to be sent out sometime next week, that any new subscribers who join in the meantime will automatically be included in your scheduled campaign.
You can confirm that this setting is enabled by 1) clicking the Subscribers Filters expand button and then 2) looking to see if the New Contacts checkbox setting is checked. If it is checked, it is enabled. If it is not checked, then it will be disabled.
Don't want this setting enabled on all campaigns?
If you do not want this setting enabled automatically on all campaigns you can simply navigate to Settings > Message Settings to disabled it. Near the top of the message settings page you will see "Send to new contacts ", simply uncheck the box.