This will prevent issues with service username formatting when access permissions are granted to the guest state. While users without mains cannot activate a service they could still retain an active account and it's possible to schedule a nickname update task which would subsequently error out.
Also it seems like a security issue if someone has a service account but their EVE character isn't known. cc8a7a18d23e9beb6e0a498a314e4c3bcae3f700 prevented accessing the services page without a main, now this ensures users don't have an account to manage.
