SCR DEF added to your Diesel fuel Tank?

Take a look at this DEF tank located as far from the OEM Diesel fuel tank on the Thomas Bus HDX as possible.

Do you know what damage could be done if SCR DEF (Diesel Exhaust Fluid) was accidentally added to the Diesel Fuel Tank?

What if Diesel Fuel was added to the DEF Tank?

SCR face plugging? Ruined SCR? Failed Engine?

The DEF fluid is very corrosive and once it makes its way into the fuel system the damage will cost you well into the thousands, what are you doing to prevent this from happening?