Use this to be notified each time a volunteer checks in via VSys Kiosk or VSys Live. By setting Only if late... you can see only those who are checking in at least some time after their scheduled assignment start. This only works for assignments, not for checkins based on job associations, walkup check in jobs, etc.
One notification is generated for each check in meeting your criteria here, each with the volunteer's name and information about the check in.