is a 'rake agreement' broken when a new player sits down?

[Bulbarainey]

I was at O11 the other night, playing in the $40 NL game, and got up and left after it was short handed and $3 was still going down the drop. $4 usually does, and the blinds are 1/1$. After watching my friend play a bit, the game gets super-shorthanded, and the floor came by and bought into the game. He asked me why I didnt want to play and I said the rake is killing the game, and he said "allright no rake," then a second later said, well one every other hand for "the cameras." I agreed, sat down and played, we play a few hands, I lose a bit, another player sits down, and without anyone saying anything I notice the drop going back up to $4. So is a rake agreement generally over anytime a new player sits down? or is this not legit?