In that case, the right person got a can of whoop-ass.
I once witnessed a guy throwing McDonalds trash under his seat. He appeared bigger than me but I couldn't contain my contempt for the asshole. I asked him firmly but within the confines of politeness if he thought that throwing his trash under the seat wasn't an affront to every user of the streetcar, including myself who had to deal with his garbage.
He quickly escalated the situation by shouting obscenities at me and left the trash on the floor. During the rest of the trip, every now and then, he would turn around and shout more obscenities at me. I got up, picked him up by the back of his shirt and threw him and most of his trash out the streetcar at the next stop.
Another guy got up when he realized there was going to be a fight but luckily no blood was drawn, only the loser's ego broken. The guy sat back down without having to intervene and told me he was itching to give the other guy a knuckle sandwich.
Transit etiquette is pretty bad in Toronto, hence the new higher fines. Shouting a conversation into phones, leaving trash behind, putting feet on seats, taking up more space than needed, standing in pairs on escalators.... grrrr.... it goes on.
I ended my subscription to the Metropass and mostly walk now, sometimes take a streetcar, hardly ever the subway and joined ZipCar. Problem solved.