In an air conditioned dojo that was to say the least "secure" from any outside enemyflintknapper wrote:+1
Under the best of circumstances, knife is hard to defend against. Even someone untrained (but committed) is likely to cut you. Take a person marginally trained, and you get what TX said " you're gonna get cut".
I believe that the common misconception when people feel that their weapon can be racked is that the fight is going to have a warning and some distance that will supply time. From the little bit that I witnessed...a skilled person with a knife will close that distance before the threat is even known and erase any chance of someone offering resistance.