Required Love offering

by RJ
(Florida)

My organization uses a church building that is offered to us for free.

My organization REQUIRES each family to pay a set amount twice a year as a "love offering" to show appreciation to the church.

If the money collected is required (compulsory with specific minimum amount designated vs. voluntary) in order to participate in the organization, is the money collected legally considered a "love offering" or should it be called a fee?