Unless I'm mistaken, if your character is good at it, you can just reverse-pickpocket the items in their inventories. The next time you're around, they'll be using them.

In Solitude, I pickpocketed all the steel arrows from the guards and replaced them with Daedric arrows. Once this is done, they make you unlimited daedric arrows from 8a-8p each day. Just stand near them firing arrows in the castle and collect them. I get 50-100 each day. I don't need to steal the stuff back. I have everything Daedric. Every weapon and armor and double enchanted.

Known trick. But, since you know it as well, then you know how to equip guards & stormcloaks with daedric armor

I on the other hand, have a thing with ebony arrows. But I prefer to "contribute to the local economy" by just buying them

I thought about bringing my other daedric stuff and doing the same to the guards. I might try it tonight.