I haven't entered tournaments here since 2006 so I wouldn't know after that. Before 2006 though the walker rules were thoroughly abused, which is why many other tournaments either got rid of the walker bonus or made it lower.

A 200 kg bot will always beat a 100 kg bot if they're built equally well, even if it is a walker. Imagine if Son of Whyachi were allowed 50 kg more mass. It's ridiculous.