In theory they could, but in reality they can't.
No insurance company would be willing to take on the risk of insuring a gangbanger unless they could charge a cripplingly high premium. I could get an underwriter to insure G-Thang Daddy from the Cold Crush Posse, but he would charge me a premium of $30,000 a month for a $300,000 policy.
The market solves the problem before it gets started. Until the government steps in and says it's racist to charge such high premiums for G-Thang.
If an insurance company let your wife buy insurance on your life they owe it to you to tell you about it as you're affected by the insurance.
I'm completely unaffected by the insurance - I'll never benefit from it and I'm not paying any premiums for it. It only becomes important if my wife intends to kill me, in which case I have bigger problems than not knowing if I'm the subject of third-party insurance.