Reuse Case: Teaching Assignments

Art students in a seminar are tasked to develop assignments for teaching in the arts. One of the students ask whether it was okay to (re)use assignments from others discussed in the seminar in their own teaching. The group of students decided it was okay and agreed subsequently on setting up an open source pool to support each other by not having to reinvent the wheel. Pitching this plan to another student group, the authorial status and ownership of teaching assignments has been discussed and asserted, with the rationale that individuals have put labour into developing the teaching assignments. Do I lose something by sharing my teaching ideas, or do I support others and get supported in return?