It's counterintuitive, but I've heard an explanation that the alternative - they decide to dispose their cigarette into the bin full of flammable paper waste - is much worse.
Possibly also: in toilets antifreeze such as methanol diluted in water can be used for freeze protection at low concentrations but is flammable and hazardous at higher concentrations.
Possibly also: in toilets antifreeze such as methanol diluted in water can be used for freeze protection at low concentrations but is flammable and hazardous at higher concentrations.