did you bother to read the article? we're not talking about hiring for startups. We're talking about hiring for police/emergency services. Having a selection bias against hiring honest cops sounds like a problem to me.
I get the liability issue, even if I think it's dumb, but I honestly don't think occasional drug use should have any bearing on even emergency service jobs. Yes, I am ok with my potential ER surgeon smoking a spliff to relax after a long stressful day.
If we as a society were more open and accepting of this, responsible users wouldn't feel the need to lie and we wouldn't have this problem.