I would just note that some professions require their people to be drug free and those people are tested for, amongst other things, pot. A person who is exposed to second hand pot smoke might test positive and this could be a problem for them.

Since this is FT, imagine if your pilot smelled of pot as s/he entered the aircraft (the smell does cling to clothing, after all). They might just get pulled from the flight (can't afford to take chances) and find themselves peeing into a cup. Depending on just how much smoke infiltrated into their room, they might fail the test - possibly with serious consequences to their career.