A couple of comments on Brett's comments:
Most of my flying is done in the corner of an RC field, with RC guys in attendance. The last time I flew I brought a stooge (hastily built, but oddly enough it had a spring clip that positively retains the plane and can't come off without a good firm pull -- imagine that). They'd never seen one. Even though these guys like me, and are quite happy to launch for me, I got over twice as many flights in as I usually do because I was launching by myself with the stooge. Flying in the presence of folks who's ears are attuned to the sound of a screaming model engine thunking into mud (or flesh) takes care of a lot of the safety issues.
Brett's advise was to pull the cord, and toss it off away from you. I have always (well, ever since an unfortunate accident in my youth) set things up so that the plane is about six to ten feet outside of the normal flying circle for launch. That gives me room to pull the cord, gracefully drop it right where it lays, and walk to the center of the circle over the course of the first half lap or so. That puts me well away from the cord -- and I haven't had any problems, ever.
I don't know much more to add. Someone here has a design for a stooge that's controlled by a remote door lock system bought at an auto parts store. The general concept made me shudder at first, but he has the stooge set up so that you have to push two buttons in sequence to release ("door lock" then "door unlock"). Done right, any extra chances for inadvertent release should be balanced by the "no chance" for tripping or tangling one's stooge line. If I weren't a tightwad and a luddite I might give up my $1.00 worth of string, scrap plywood and screen door parts for his high-tech solution.