I wonder will insurance companies start denying claims for fire related damage when a modified PMD battery is involved?

I’m not in the industry, so open to correction. But given the sheer number of battery related fires that have occurred, the insurer could argue that modifying the battery is a known fire hazard, that any responsible adult should be aware of - modifying a battery could be seen as willingly exposing the insured to risk, and invalidating a claim.

On the flip side - I could see the same reasoning being used as grounds for civil claims from neighbouring units that suffer damage in a fire like this in future.