Smoke Detectors
Well the cabin announcements I hear say, roughly, "Do not smoke in the toilets, it is forbidden and smoke detectors are fitted in the toilets." The implication is that it is to detect cigarette smoke and it would obviously detect a burning waste bin as well.
Both acts, smoking in toilets and using mobile phones, are illegal and to some degree dangerous. I don't think we are going to get anywhere arguing which is the more dangerous or anti-social! In either event call the cabin crew who will have a laid down procedure to follow.
Aircraft may have crashed from electrical inteference; systems have been affected to a degree noticed by the crew perhaps some "Cause Undetermined" crash has been caused by this?