Seems to me...
The purpose of this article is not so much to handle incidents of "unchaperoned roommates". That situation is pretty rare in JW-dom, I think.
I suspect the real purpose was to reinforce the peculiarly JW notion that any and all "worldly" people fornicate like horny rabbits with hormonal imbalances, at any and every opportunity, with multiple partners, of the same or opposite sex, and that any 2 people left alone for more than 5 minutes will tear each others' clothes off and copulate wherever they are - home, office, Walmart fitting room, you name it.
This serves to reinforce the idea that the JW organization is a crystal clear beacon of light, so morally superior to "the world" that it simply must be God's organization.