Hacking: preventive manoeuver

An example of hacking, within formal or official circumstances, in order to prove that a system does not work. How does the behaviour comply with criminal law? Motive, whether good or bad, is not intent... "Researchers hack 'tamper-proof' PIN terminals" (26 February 2008) http://news.zdnet.co.uk/security/0,1000000189,39352920,00.htm