There are also warning labels all over the various fill caps on a vehicle. "Unleaded gasoline only". Which are like real-world input validation. It's just not f

There are also warning labels all over the various fill caps on a vehicle. "Unleaded gasoline only". Which are like real-world input validation. It's just not feasible to check the fluid before allowing it in. But is is feasible to add a data validation layer to your application.