A few years back more fires and issues were more widely known but that was due to people not knowing how to care for their lipos. Chargers back then werent as smart as they are today. Back then you hade to know your cell count, MAh, amperage and set your charger accordingly. most fires I read about was because someone set a charger wrong. Set to charge a 3s battery with a 4s setting.
you hear less and less about battery fires now days mainly because of alot of anomally detections that are built into chargers. I have a charger and if something isnt right, it will stop charging and it also has a auto cutoff when battery is fully charged (few years ago, that was a luxury for a Lipo) Today, when I hear of a fire, its usually because of a damaged battery or wires getting crossed. Still, you do have to be careful with Lipos and respect them.