slippery slope may be a logical fallace, but it can also be disturbingly correct
http://www.cnn.com/2009/CRIME/06/06/jersey.police.beating/index.html

Now consider the outcome. The guy has clear physical signs that he was beaten. Bruises all over one side of his body, visible medical signs he was abused.

What if the police officer had used a taser instead? A huge electrical shock that disrupts the nervous system and fires all your pain nerves receptors simultaneously, being tased is incredibly painful, just as if not more so than a physical beating. However, there are no physical marks or evidence that the police officer just administered an electrical beating. With every click of the officer’s finger, that is another beating that you cannot prove you received, you just feel it. The officer can deny it, you have no proof, therefore no recourse.

The U.N. has already referred to tasers as torture devices. We give them to everybody with a badge and hold no one accountable for their use.

I remember when tasers were first introduced to law enforcement in the United States. There was a lot of debate about it, and every taser supporter and proponent said that they were a replacement for deadly force. The justification for deploying them was that a police officer would use a taser rather than fire their gun. Opponents said that they would be used routinely to get quick compliance and as punitive measures, essentially allowing the police to deliver a punishment without due process or accountability. Opponents said the ease of use of a taser and lack of evidence of its use would lead to them being used casually for all situations, particularly ones that never would have required the use of a gun.

Now that tasers are everywhere, it is quite clear the opponents were right.