[BHS_STopping]

If we're going to be loose with our definition of "legged," I would consider Beatty's 2002 machine to be a "crawler" of sorts. Check out some of their videos on TBA, it's really an elegant mechanism. However, they weren't champions in 2002 because of the qualities you indicated. In fact, their machine was simply very slow and powerful, but guaranteed a victory if they could snag all 3 goals at the start of a match.

Their mechanism was simply two sets of one-way shoes which slide forward on the carpet. In this sense, the robot could easily be pushed forward, but impossible to stop if you were pushing backward. It would take a minute to get where it needed to go, but the simplicity of the design (469's mechanism reminded me of this this year) was just phenomenal.