State law specifically allows for fees for participation.
Hawaii Administrative Rules 8-32 Collection of Authorized Fees and Charges.
8-32-1 Definition. As used in this chapter, "co-curricular activities" means student activities which are authorized by the school principal and which complement classroom instruction by providing learning experiences which meet individual needs and develop citizenship skills and positive attitudes in less formal settings. [Eff 8/23/84; comp 9/1/95; comp 9/28/02] (Auth: HRS § 302A-1112) (Imp: HRS § 302A-1130)
8-32-2 Fees and charges for co-curricular activities. Schools may assess and collect special fees and charges from pupils for co-curricular activities. The maximum allowable charges for class dues (middle/intermediate and high schools), student association fees, and school club dues shall be established by the board of education. A school principal may establish fees and charges at amounts which are lower than the maximum amounts allowable under this section. [Eff 8/23/84; am and comp 9/1/95; am and comp 9/28/02] (Auth: HRS § 302A-1112) (Imp: HRS § 302A-1130)
Hawaii Revised Statutes 302A-1130 Public schools special fees and charges.
(a) The department may assess and collect special fees and charges from students for co-curricular activities. (b) Special fees and charges collected from students for co-curricular activities shall be deposited into insured checking or savings accounts and expended by each individual school.