Normatively, suicide is shameful in modern society. By contrast, I don't think most suicide-victim families (or their social network) are thinking about the life insurance proceeds at the time (within a week?) that the coroner is determining cause of death.

I know I've heard of a survey of coroner in which some substantial percentage (20-50%, sorry don't remember better) of coroners reported that the following had ever occurred in their career: they believed the cause of death of the body they were examining was suicide, but listed the cause as accident.

I can't find that survey in a quick search, but this research result talks about the effect of elected coroners on cause of death determinations. Specifically, elected coroners were slightly less likely to declare suicide as the cause of death.