1st March 2010, 01:25 PM
Do you also then consider it an invasion of people's civil liberties if they are tested while driving? Personally I'd be pretty concerned if I suspected someone was on site off their face and using heavy machinery! The fact that they consider it worthwhile at all suggests that it has been an issue in the past. Or indeed it could be part of a creeping Orwellian nightmare, if you believe in such things...