Our group makes quilts at home and then brings them to meetings to show them and donate them. The only requirement to be a member is to donate three quilts a year. Most of us donate many more than that. We make lap quilts so three a year is not a big deal.
Sounds like maybe your guild leaders want to encourage "sew together" days and are using this as an excuse. As long as the group as a whole is making and giving quilts to charity, there shouldn't be a problem with keeping a tax exempt status.