is it a fire hazard for my neighbor to put her christmas tree against a steam heat in the hallway?

one of my neighbors likes to put her christmas tree up by the heater every christmas, its near the laundry room, and out in the hallway, its not a real tree but she puts it too close to a steam heater, i tried to get her to put it further away but she wouldnt, she wants everyone outside to see it. the last couple of yrs the heat wasnt even on there but this yr they changed it so they made knobs to turn the heat on and off , it was on 5 which is the highest, about 2 days ago i got fed up and went to the knob and turned the heat totally off, so far noone has even noticed it, guess it dont get cold there when its off. i was afraid of it starting a fire so i just turned it off, do you think i did the right thing?