Slightly off-topic, however I used to rent from a place that didn't have their aircraft insured at all. They made you sign up on your first flight (pretty much the TIF) that you'd be up for about $3,500 if you damaged the aircraft. It was thier own pseudo-insurance policy really. Perhaps your mob is doing something similar. They said insurance was simply too expensive and most of their incidents were of a low dollar value. The aircraft were around $50k-$60k in value.