You can simply use anchored and passworded audit log secure containers with a simple password like “12345” that can even be showcased in the title (name) of the container. The log will show exactly when and what character opened the container using the password (or even show if they failed to open it due to incorrectly typing it) so the organizer can confirm if the person took the waypoint or not even without an organizer being there at the time thus can use as many waypoints as one prefers.
Similar to how I’ve used such containers as a sign-up method in my lottery giveaway: