The Yoshinkan school of Aikido has an unoffical friendly rivallry with the local yakuza-gumi's. The senshusei and uchi-deshi would stalk the streets of shinjuku and kabukicho look for yaks to pick fights with, just as Shioda Gozo once did in his youth. The Yakuzas are good sports and goes along with it, and they get beaten up due to lack of train. They then send more veteran guys to beat our boys up, and we call our sempais over. It goes back and forth, and both sides gain valuable combat experiences. No hard feelings though, since they respect Shioda kancho and the Yoshinkan name. It's a tradition of sorts, since those students eventually become riot police officals, and the Yak's lifelong rivals.
If the training allows you to take on Yakuzas on the streets of Tokyo, do you think some drunk thug will stand a chance?
Mind you though, it depends on how hard you train yourself!