How insured sometimes behave as reinsurer to insurance company , hence shre them premium and claim .?

The insured in case of under insurance insured his property with value less than actual value and pay premium less than actual as if he share the insurance company part of premium .The same insured in case of claim share the insurance company part of claim when the company apply average clause. So insured by under insurance behave indirectly as reinsurer doing their same job to insurance company by under insurance .

Best wishes.