> In 2016, General Motors took the lead among automotive manufacturers by introducing the Rear Seat Reminder, a technology designed to nudge drivers to check their back seats as they exit their vehicles. It uses an audible alert and a front panel message to tell drivers to check the rear of their vehicle for occupants.
> Rear Seat Reminder technology became standard on all new Chevrolet, Buick, GMC, and Cadillac four-door sedans, SUVs, and crossovers starting with the 2019 model year, and also will be standard on all 2020 model year GM pickup trucks, said GM spokesperson Phil Lienert.
> Kia, Nissan, and Subaru offer rear-seat alert systems in many of their models, according to Car and Driver, and Hyundai announced on July 31 – National Heatstroke Day – that it planned to incorporate the technology across all models by 2022. One of Hyundai’s newest innovations is the Ultrasonic Rear Occupant Alert, in which a sensor can detect the presence of a child (or pet) and activates a loud horn if the driver leaves with the child inside.
I'm not sure where you live but in the United States, in some states, children are required by law to ride in the back seat of an automobile until they are, I believe, 8 years of age. I believe that various state and federal agency recommendations are for children to ride in the back seat of an automobile until they are 13 years of age.
Presumably, then, parents are not putting their young children who cannot operate a car door into the front seat of a car and leaving them.