Drug Testing: good for parents, then good for the Police

The one objection to ending prohibition that you often hear is the increased use of driving under the influence, with the police being unable to detect drug use by the roadside like they can with drink.

Breathalysers are portable, but drug detection was always a wee bit more problematic. This begs the question as to what the Police having been doing all this time to detect driving under the influence of drugs until now?


Well ask no more -

http://www.telegraph.co.uk/health/healthnews/8017473/Five-minute-drugs-test-can-tell-parents-if-their-children-use-cocaine.html



However, a quick look at the Daily Mail's comment page suggests that these kits could be used as another tool in the fight to control drugs and keep them illegal. (Comments were accurate at the time of publication of this article on LBR)
http://www.dailymail.co.uk/sciencetech/article-1314041/Vantix-Parents-drug-test-childrens-saliva-cannabis-cocaine-use.html?ito=feeds-newsxml

Of course this assumes that these tests work as advertised. Is it possible somebody may be found guilty on one of these machines, and yet they are in fact innocent?