Single post in Regarding Art Theft

Can someone tell me if I'm reading this right? In the case of commissions and bought art (therefore, I own the art now), I don't have to credit, although the staff would prefer I did? Right? I'm pretty sure that's what I'm reading. Correct me if I'm wrong. Now, uh... Is proof of permission required for all instances where my boyfriend draws me something? He's verbally said it's alright, since we live together. So, would that work? Or would I need him to provide a written source to show that I have permission to use it?