Notifications for unfilled / unscheduled role

I would like to request the option to have alerts / notifications sent to the relevant person if a scheduled role remains vacant within a certain time of the role being scheduled.

We enter the year's rostering in at once and sometimes there are vacant roles for various reasons throughout the year which may get overlooked prior to a service. Also, if introducing self-sign up, there's the potential for a role not being filled prior to the service. Therefore, it would be helpful to have the role leader / service manager for that service alerted within a timely fashion of the role vacancy.

Related Threads:

Planning Accept / Decline Notifications to be received by nominated person / role
Allow black out / block out of scheduled / rostered roles to indicate no volunteer required
Set number of roles available per Service
People - New Permission Set - Let Volunteer Self-Sign Up
Individual Sign Up
Request sign-up for a role in a service

Made a mistake in the title... should read "Notifications for unfilled / vacant role prior to service"

Addendum:

Also have relevant person notified if an 'Invitee' has "Not yet responded" to an invite within a defined deadline / time period prior to the Service.