I think that it should be possible for apps to adjust how RCs are used including discounting transactions using their own stake. For example, SMs might want to reduce their transaction costs for users to encourage usage and since they don't suffer spam, that is fine. The user gets assigned some factor or reduction as they login which is usable only on SMs and returned to the pool on logout.

Thid means that with minimal SP (which can still vote), a lot of RC bandwidth can be created at any one time to empower users.