Hi. (Poor English. Please Understand)
I made render layers like upper images. And I check renderable except for 'Masterlayer'.
But when I render that, 'Masterlayer' render started.
I don't get it what happen is.
Acually, there is one more problem.
When I drag lights tab from masterlayer to another renderlayer, it looks done in renderlayer, but there is no light in renderlayer that I drag. Only lights tab is in renderlayer, no lights. (like Bottom Images)
Please check this bug...