cc wrote:

> I don't see what is an urban legend here.

Being an urban legend refers to its nature, not its truthfulness or
untruthfulness. See

http://www.snopes.com

for any number of true urban legends, mislabeled urban "myths" by people of
some countries.

Be sure that though there may not be "a" law regarding the legality of use of
martial artists' skills, there are professionals and bodies devoted to martial
arts in law, and other pages which concern themselves with liability in an
altercation. If people cared, they might consult such as

http://www.karatelaw.com/index.html
http://www.ittendojo.org/articles/general-4.htm
http://www.mntaekwondocenter.com/resources/tkd-and-the-law.html

The first and third men are professors, and the second is a prosecuting
attorney, all masters or instructors in Asian martial arts..

http://www.tafkac.org/faq2k/legal_2007.html

from another urban legends site, has cites to conclude "Documented: A criminal
defendant's experience in boxing or the martial arts may be relevant to
deciding whether the elements of a criminal offense have been proven."