Several years ago while at an aikido seminar I witnessed 2 younger (mid to late 30's) and very talanted / high ranking aikido teachers (one a 4th dan, the other a 5th dan)get into a fight during the seminar while training with one another. Aparently the two had a lot of "history" and hated one another.
Things got really ugly and puches started flying. Really sloppy wild punches I might add. They were both swinging for the fences. A few seconds latter they were both on the ground doing what looked like really bad ground and pound MMA until they were pulled apart. Not at any point did either one of these guys do or even attempt anything that vaugly resembled aikido.... and the fight also ended up on the ground.
I'd be curious to know what teacher or organization they were with (actually I could probably hazard a guess here). It's telling that two people can advance that far in aikido apparently without having learned anything from it about how to behave in a real physical conflict. That story is a perfect example of what's wrong with aikido today.