For the automatic breaking, does it stop the car or a warning?

A nephew is considering the Mazda CX-50. For the automatic breaking, it is just a beeping flashing warning or does mazda SMART BRAKE SUPPORT WITH HEAD-ON COLLISION MITIGATION stop the car?
 
Certain criteria has to be met. Can kind of suck when it dynamites the brakes when driving fast in curves because it detects the gaurd rail
 
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