I thought you were doing that over the airwaves. My mistake on that, as that's an autism moment. For just the store or something along those lines, you don't need to do so. Sendo is absolutely fine with it. I think CC BY is only enforceable if there's some sort of video, movie, livestream, etc. that basically has it displayed. For a shop like yours, he can't control that, since that's what the license is.
Sometimes, for a few of them, they're ARR, but he doesn't mind that either.
Huh... it's a Crytek game (since it's made in CryEngine 3), which probably explains some of it. It's on Steam for 85% off, but Sendo and I don't really buy video games all that much to begin with. Looks dope, though.