Actually I happen to know that this is untrue as my wife is a substance abuse counselor and has seen people test positive from second hand. The equipment she uses gives actual numbers so they can tell if its second hand or first however they have to mark either pos or neg. There's no shades of grey when your on parole. Just an FYI.
You are correct. But it is wholly contingent on the type of test being taken. Anything government related should/will pick up exposure to second hand smoke within about 30 days.
Ran into this a lot myself when I was younger; recruiters would try and get me into government tech jobs, but I always hung out with pot heads. Per the guidelines they give recruiters candidates need to have no exposure to any 420 smoke, for 30 days, period. I'd assume parole tests would be along similar lines, especially since the parolee is supposed to avoid contact with criminal elements/activities.