Microsoft has a patent issued in 2012 for this very topic...and as you predicted, there were many news articles and questions about ethics brought up. [1]

Given the market share Google Maps has, the economic fallout from them suddenly avoiding certain areas deemed "unsafe" could swing billions of dollars annually from one set of businesses to another.

[1] https://www.npr.org/2012/01/25/145337346/this-app-was-made-f...

They probably do, even just by factoring in how popular segments are. I agree there would be a shit storm if they labeled certain paths as safer though.