I suppose prosecutorial discretion is the only solution. Biased/unreliable as it may be.
On the technology side, I'm thinking of two bluetooth (or similar) enabled wrist bands. One for the kid and one for the mom/dad. When the device loses connection to the other, the parent's band beeps and must be manually silenced. The kid's band could be connected with the car via bluetooth so the only time the alarm can be activated is when the kid's wrist band has been connected with the car in the last 10ish minutes (adjustable). Though if I were a parent I'd be worried about losing a kid in general too.
If there is one company that has everything aligned it’s Apple - privacy, miniaturisation, health and ethics. Some very low tech version of Apple Watch could do.
Trouble is a lot of moms are extremely crunchy and selling something like that would be hard.
If it’s legally integrated in car seat then it’s much easier.
If someone becomes serious about solving this problem with tech, I want to point out that children are left on buses by schools/daycares with tragic consequences as well. Maybe there is a general solution to both somehow.
I am a parent and have a vested interest in this. That sounds like it can work, though my car and my phone do not reliably connect via bluetooth and I am sure there are other cars like that.
On the technology side, I'm thinking of two bluetooth (or similar) enabled wrist bands. One for the kid and one for the mom/dad. When the device loses connection to the other, the parent's band beeps and must be manually silenced. The kid's band could be connected with the car via bluetooth so the only time the alarm can be activated is when the kid's wrist band has been connected with the car in the last 10ish minutes (adjustable). Though if I were a parent I'd be worried about losing a kid in general too.