I know you know but although Shodokan tanto randori takes things closer to the edge than most tanto dori some people tend to forget that it is afterall a rubber/cloth knife. When it gets to shiai the rules are geared to the idea that it is a real knife but even so people often take liberties. Most people understand the difference.
I hinted at it in a previous post on this thread but some of Tomiki's tanto dori techniques (kata) are interesting to say the least. Half of the Nidan training is learning how to target with the knife including my favourite "the yakuza belly thrust" which I understand is and always has been quite popular amoung certain wayward individuals. Even here though - I am not sure some of the tanto dori techniques are worth trying in the field exactly as they are (the neck trap one gives me the willies).
Back to the dogma - randori and kata togeather come to give you a fair idea of what is involved in knife fighting. It might not make you a better knife fighter but it sure opens your eyes.
Last time someone threatened to use a knife on me I just stood tall and stared him down. The little yak wanna be backed down.