You do get loot for killing a scout. But you don't get a coin for killing a scout because there is no battle occuring. It's in the uFAQ.
Even if you oppenent have like a +12 military bonus, and you attack a scout with 1 single army, so you have 3 units, let's say you have 3 power 2 units and no military bonus. If it was a battle, you will lose the figth (12 vs 6). But when you move on an ennemi scout, there is no battle occuring, so you do no count the military bonus and you win by forfeit.
On the other hand, if you attack an ennemy army, or a group of ennemy armies, or a group of ennemy armies and scout (on the same square), and your oppenent haves no more unit cards. A battle still occurs and the military bonus are counted. So if he haves +12 military bonus, and you only have 3 lvl 2 units for the battle, you will lose the figth (12 vs 6). He will get reward, he will get a coin if he haves code of laws, your figure will be destroyed, and he will not lose a single figure because he didn't lose cards. In the case where you win that battle, you get reward and a coin even if he don't have unit cards to play.
The overall rules is : a battle occurs when you have to count military bonus, power of each surviving troops, to decide the winner of the battle. This don't happen when you move army on a poor standing alone ennemi scout (or on 2 poor standing alone ennemi scouts).