I think you are underestimating how heavily guarded army supplies are.
But if it is only affecting provisions, I doubt people will care much about this. Just a minor annoyance which you can deal with by looting for food.
As for looting, I think there should be some big difference between lenient, normal and strict.
Lenient granting a huge morale boost + doing unwanted damage.
Maybe there should be an option for TLs to decide how they want to punish their own men as well. Execute arsonists or something XD.
