I also suggest adding columns to the report showing departments where they're volunteering (if they're signed up for any shifts at all) and number of shifts.
/dev/null is what gets put in if a lead signs up a shift without putting anyone in it. There is a giant warning dialog to not do it basically, but I do let them...
I also suggest adding columns to the report showing departments where they're volunteering (if they're signed up for any shifts at all) and number of shifts.