Random Drug Testing

I work for a mid sized oil and gas company in central Alberta. My company does have a very comprehensive drug and alcohol policy however, we do not do random drug testing as there is zero evidence of a substance abuse problem among my employees (among other reasons as well). We do some work on oil sands sites and my field personnel are tested prior to arrival. With the Suncor/Unifor battle over this issue, Suncor sent a ‘mandate’ to those of us who work on their sites that we MUST implement a random testing policy/program (which requires testing 50% of my entire staff at $130+ per test) when there’s absolutely no justification (zero evidence of substance abuse) for it within my organization I believe is completely unacceptable. My question is why is their problem and failure to control it allowed to affect the rest of us when we’re not in the same boat? Could we even legally implement such a program when there’s no reasonable cause for it?