For example, if you knowingly buy stolen property and benefit from the discount in price are you in some way complicit in the original act of aggression?
What if the benefit is indirect? For example, I buy stolen property for the purpose of returning it back to the owner and obtain a reward. Does this promote or hinder complicity?
It still promotes complicity because the thief gets rewarded; you're only shifting the onus of victim-hood from the original owner to yourself. Also, if there are no changes in the system, that same owner can (and most likely will be) victimized again. So, in essence, you're causing the owner to be traumatized twice!
Yup, I can see that.
Complicity is being involved in illegal or wrong activities. While you did not steal from the owner, you paying for the merchandise is you normalizing and profitizing the bad behavior. This will lead the culprit to continue such behavior. Profitizing might not be a word but you know what I mean lol.