Fire precaution is indeed very important with Lithium. I charge huge 5000mAh LiPo 4s cells for my 7-up bike light and use a LiPo-Safe fireproof bag (
Battman Li-Po Safe 30x23cm Bag ) when doing so, to contain any explosion or fire that might result from a faulty cell. I usually don't bother putting protected 18650s in the bag because I use a good quality intelligent charger. ( the cell's protection circuit
and the charger would both have to fail to overcharge and explode ) but if my daughter was still living with us I'd certainly make the effort for added peace of mind. The bags are cheap insurance and will significantly reduce the damage to surroundings, so I'm told.
Cheers, CC