Hoping to get the whole, I got this great Idea but because of my router/ISP/whatever... I can't. Being RP Unlimited is open for the host to just assign head admin and then leave it run.
Not all hosts need to be active on the server to host it. But it helps if you would like to join the server being it leaves a link of interests shared.
(On a side note, I am able to host but have limited ports right now. If I see something that interests me I might offer but this is rare.)