The park has the ability to see people using flash photography on the ride and call them out for it using the ride announcement system, so I think they could've seen someone breaking off the finger. In all reality, we don't know that it wasn't immediately caught and that said guests were not met by security at the exit. The broken drywall in the queue would've been much harder to see in the moment. At this point we'll just have to see if Kings Island fixes these parts or not.
As for the possibility of the finger falling off on its own, there's a possibility that it could've been due to an issue with the hand mold. It might've also been an issue from the animatronic's installation. Both situations are unlikely, but anything is possible; again, we don't know what happened to cause any of these issues.
I've been thinking of making my own version of BryanJay's Halloween Haunt overlay for PT:ON using my (admittedly limited) video editing skills. Most of it would be the same, but I have some additional thoughts of what could go in there. It'll also be a good way for me to dive back into video editing.
Mainly, I'd add the toppling boxes/Bosco's door sound effects and do some alternate sound mixing. The stage scene could use one of the other songs from PTE. I think it would also be fun to see if I can mimic the difference in sound quality between in-car voice lines and diegetic lines.