I’m gonna add this here in case it helps anyone else.
A friend of mine uses a long dog leash to prevent her from forgetting her kid in the car. She uses the handle end with a loop and ties that end to the carseat and then attaches the hook end to her belt loop or purse. Now she can’t leave the car without acknowledging the carseat.
She just leaves the dog leash attached to car seat all the time and attaches it to herself when she puts on her seatbelt.
I thought it was a great solution that doesn’t involve removing shoes or buying a new car with seat sensors. Hope this helps someone else, or at least gives them peace of mind if they choose this method.