There is nothing in the conditions of use for the lower Rogue regarding a prohibition of sending a boat out early. I checked because I thought it was against the regs. but didn't see anything about it.
I thought it was against the rules because of an incident last summer.
We generally leave Grave Creek early to avoid any crowd on the ramp and because we are always excited to get on the river. Last summer I was approached by a young guy who was putting in for a guide service. He was sure we were heading out ahead of our party to get a camp. He didn't believe me when I told him it was just our single raft. He said he was going to "turn me in".
It was pretty clear that he was doing exactly what he was all over us for doing.