Harper still comes out of it looking better than if he did a deal with Fan Duel, or if the VIP host had actually purchased it as a business message (which might have been more closely vetted). I find it semi-plausible that he barely realized what he was reading. He'll probably sue both of them and Cameo will also sue Fan Duel. And Harper should also fire whatever member of his social media or video team let it get past them.
Then again, given Fanduel is not only an MLB partner but also had the naming rights to nine MLB partner TV networks for a while, why would it even raise an alarm bell to partner with them or read their name? There's just no way in which everyone in MLB doesn't stink to the high heavens for the whole association.