Since this is a fundraiser, only those working the event should be let in free. If you start giving free passes to a large number of people, it defeats the idea of a fundraiser. You're putting on this event to raise money for the school, not to provide free entertainment.
How much are you charging for admission? If the staff members who want to be let in free helped with this event in any way, perhaps you could offer them a discounted admission price, or offer the discount to the staff as a whole if that would alleviate hard feelings. Good luck!
Are there any guidelines in place for who gets free passes to ticketed events? We have a beauty pageant fundraiser, and school staff members expect to be let in free, even if they are not working at the event. :confused: