In Chris Caile's opinion piece, http://www.fightingarts.com/reading/article.php?id=306 he points out that like any endeavour, MA's require feedback to monitor progress or desired results.

Karate, is said to be taught using two man drills. Which are very effective. What is also said, is that partners are not expected to interfere. This is a mistake. Athough people can take the liberty to far, and be annoying or counter productive, it is better to let those training not only bend the rules andchallenge the ability of their partner to apply a technique - for example, the speed or timing of a punch, or the ability of a armbar to restrain an assailant. This is essential feedback and this more laissez faire approach to practice encourages people to innovate for themselves and to make their technique in less controlled environments.

If ettiquete doesn't help foster self preservation, it should be thrown away. Low level contact sparring has it's place, but full contact is indispensable in terms of distancing and building up toughness. Unusual attacks, retaliations and counter attacks should also be taught. Streetfights are unlikey to begin with a beautifully executed side kcik or reverse buch. Self defense should be taught so that you can keep pace, but once you have got the basics right, make it so it would work in an encounter, against a paticularly aggressive or stronger aggressor.

But, short of joining police forces, or engaging in streetfighting routinely, how else can we get feedback controls on our current performance?