If this actually works it will be a huge win for everyone. Right now, for example, if you work construction in a state where weed is legal, you cannot partake even in your free time without risk of losing your job. For good reason too: it's better to be safe than sorry.

A test like the one described in the article would change all that. We could be safe while still affording the freedom to do what you want with your own time no matter how dangerous your job is.