NoXion
Craicy the Squirrel
The only accurate way to ascertain whether someone has been on the marching powder is via a drugs test. If you fail the test they don't say, "oh, it's probable this occurred on Saturday night so that's ok", they say "drugs test failed - gross misconduct."
Which just goes to show how rubbish drugs testing is as a method of determining suitability for work, does it not?