My son asked why I always put the lunch money in his backpack pocket but never actually zip the pocket closed

He wanted to know why I always tuck his lunch money carefully into that little front pocket every morning, then send him out the door with it flapping wide open like a tiny cash register.

Punchline

I told him it's called trust-based accounting—if the money makes it to the cafeteria, great. If it falls out on the sidewalk, well, that's just tuition for life skills.