In fairness to Mark Driscoll (I attended his church's campus in ABQ with my protestant ex-girlfriend for a year - went to Mass or Divine Liturgy every Sunday, mind you, and never received communion there or enrolled as a member - the point is I know the church somewhat), the logos that Mars Hill in Sacramento uses do actually resemble quite a bit Mark Driscoll's church.
A friend of mine who was raised Catholic and Jewish (confused parents making a compromise) and is now an open, practicing homosexual once told me how much he loves Mars Hill - he went there when he was in California, and I was surprised he wasn't so offended that he left immediately. I googled them because I was certain it couldn't be the same Mars Hill - but I saw the logo and the church website and it looked so similar I thought it was the same and never thought different until I saw this thread.
Yeah, it's probably brand infringement. And yeah, maybe a lawsuit threat isn't the way to go about it, but this Mars Hill is trying to piggyback off of the success of the other one, and if it's, say, accepting of certain behaviors that the Seattle one isn't, then it could look badly for Mars Hill Seattle to many Christians.