And snakes have died from improperly thawed F/T. And horses have died from random things being in their hay, and dogs from bad kibble, etc. Nothing is risk free. I don't think a rat could maul a snake that bad if the owner had been feeding the right size and supervising the feeding. I'd never throw a full grown rat in with a ball python. I cant remember who it is, but I think it's a mod on here, that has done something like 10,000+ live feedings and is incident free. You do it right and it's not dangerous.
I don't think snakes need stimulation. My ball pythons seem pretty content on staring into the blackness of their hides all day. The boa seems pretty content with herself by digging a trench in the aspen by the the glass and resting her chin on the edge to watch what's going on in the room.