You can also check in and check out all volunteers in bulk if they aren't checking in themselves. To do this, open the event check in screen, find your event, and click on Review Check Ins and Check Outs
The next screen will show list of all registered volunteers. You can also add new volunteers to the list. Once the list is confirmed, click on Auto Check In and Out Everybody. The app will automatically log time for the scheduled shifts for all the volunteers listed.