I don't think unarmed Aikido is particularly "deadly".
Aikido and Competition
by David Alexander
"Aikido went in the opposite direction from Judo. To quote from "Traditional Aikido", by Morihiro Saito, Vol. V, "It is a well-known fact that matches are prohibited in Aikido. This is because Aikido has inherited a number of lethal techniques from its Founder, which render matches too dangerous an exercise, and also because the art purports to place no restrictions on every conceivable movement.
If the rules are set and dangerous techniques are excluded from the matches, Aikido undoubtedly will lose its raison d'etre. If matches are to be held, all the techniques will have to be scaled down to those consisting mainly of Atemi or the contestants will have to either stake their lives or wear protective gear. A question also arises whether the form of the competition should be limited to empty-handed techniques or should also include the use of weaponry.
Even if only empty-handed techniques are allowed the techniques inherent with Aikido are too terrific to make Ukemi (rolls and somersaults in defense) possible. True, such Ukemi against throwing is made possible deliberately in training sessions. However, execution of techniques becomes uninhibited in matches and the dangers involved are obvious."
David ( not the person being quoted above)