Re: Aikido. The Martial Art.
I disagree for the most part. Most aikido techniques I have seen are perfectly legal in many combat sports. Most combat sport practitioners know when to submit. None of the locks and throws in aikido are any more dangerous then the locks and throws of bjj or judo. Seriously, I can destroy your knee much faster with a heel hook then you can cause serious injury to my wrist with nikkyo. Judo throws against a person who has no skill in falling are just as devastating as any aikido throw. See karyo's shoulder lock hari throws for an example.
I think people's bodies are more resilient then we give them credit for. I've been thrown against my will while in a wrist lock, I've been throw against my will by my aikido instructor, I've been throw against my will while in a shoulder lock. I've been submited with neck cranks, spine locks, knee bars, heel hooks, ankle locks, wrist locks of every aikido variety, elbow locks, toe holds, etc all in sparing. Some of them so fast and so hard I was sure I was injured. Only to find I was fine (or just sore for a few days).
IMHO the heel hook is the single most dangerous joint lock you can apply on the human body. It causes serious injury very quickly, and normally the injury happens BEFORE there is any pain. Yet it is a staple of bjj and MMA training.
That said, yes, anyone with the skill can cause serious injury to their opponent. It is just much harder to injure someone (hand to hand) then most people realize.