Sometimes on test cars I discover features that I didn't know I wanted until I miss them when they're gone. Blind spot monitoring on the Mazda6 was one of those features.
Here's another small thing that makes the world of difference in an over-trafficked locale like Chicago. If you are simply maintaining your position in your lane, a warning light flashes when a car enters your blind spot as it passes you. The beautiful thing, however, is if you turn on your blinker and a car is in your blind spot, there is an audible sound that puts you on the alert and has you re-checking your mirrors.
If more cars had blind spot monitoring, I have to think fewer accidents would occur by those driving texters who aren't paying attention to what's around them but think they can still drive aggressively.
Blind spot monitoring is standard starting on the i Touring Plus model ($24,240).