Accidental death and dismemberment coverage is inexpensive and as to exactly what is covered and the percent of the benefit paid for the kind of loss incurred, it really depends on the policy language and how much coverage you buy.
Young people who are healthy tend to think they are most likely to die by accident and they would be correct in that assumption. There is another component to many accidental death policies and that is the dismemberment benefit and given the Rhoden's situation, I can see this as being an additional incentive to buy a policy like this. It's called an AD&D policy and it's very common, very inexpensive, comes in many forms and since CR Sr. was self-employed (no Workers' Compensation) and he did carpentry work, car work, etc., he was at risk of losing a finger, fingers, a hand, etc. and this kind of loss would put him out of business. The dismemberment benefits tend to be quite generous under these policies and they are also tax-free.
I can totally see a wife and mother who wants to try to protect her family being very interested in this kind of low-cost coverage.
They could easily have had and afforded $1,000,000 or more each in coverage. Murder by life insurance does happen. I've seen several happen in my career, but the one I will never forget happened years ago and involved the murder of a man who had pretty close to $1,000,000 in coverage, with multiple carriers. The beneficiary on all of these policies was listed as his fiance. The problem was, he didn't know about any of these policies, and he also didn't know the woman who purchased them. She did it all through the mail. And yes, she was the killer.