A friend of mine insists on keeping a ceramic bowl on his workbench to
charge his LiPo batteries in, and it seems a reasonable precaution,
given that the failure mode involves jets of fire coming from the pack
in most extreme circumstances. Pretty much spells out the need to not
leave batteries charging unattended.

Were this a "common" occurance, I would expect that these batteries
would have been removed from the marketplace by now.

I went to an indoor fun-fly and the Li-Po batteries were being charged
on ceramic tile squares and each charging station had a fire
extinguisher and someone watching the batteries. As you say, seems
reasonable.

-Carl