Flag Graco new idea comment

I was just reading about another hot car - near tragedy about a child left on a daycare bus and had almost the exact same idea. I was thinking some kind of sensor in the car seat like cars have in the front seats to detect body weight and alert you to buckle up...but, have it in the car seats and also a thermometer to detect temperature inside vehicle...if the temperature rises to a level above maybe 85deg, and weight is detected in car seat, trigger the car alarm.