And as I said upthread, how exactly does someone decide what is and isn't loitering? If we stick to the spirit of the rule then we have to ticket anyone who is standing around taking photos instead of using the transit system for traveling (AND anyone who is waiting for someone to arrive by a specific vehicle!), which would be spiteful; and a waste of time.
And how does someone decide what is and isn't a public nuisance? As I also said upthread, the language the bylaw uses is very vague. As something of a miserable bastard myself, I could argue that someone with low quality headphones with music bleeding our of them, through no fault of their own, is a nuisance. Should they be ticketed? What about someone who on an empty subway train sits uncomfortably close to me? What about if I'm deeply religious and I see someone wearing a Pentagram shirt, or a woman showing immodest amounts of skin? At the end of the day, public transit is here to serve a diverse cross section of society, and we're not always going to get along.
If the bylaw was any good, it wouldn't use meaningless word salad but outline clearly the types of behaviours that it finds unacceptable. Leaving it up to the discretion of an inspector or constable is a stupid idea, these types of low level positions of authority are well known around the world for attracting some of the very worst types of people, petty authoritarians who couldn't hack it as cops who love to make the lives of little people as unpleasant as can be. (See also: retail managers).
It's all well and good to just say "enforce the bylaws!", but if the bylaws are vague and unhelpful then that doesn't actually achieve anything.