This is just really cool and heartwarming. OK, perhaps I exaggerate a little, but bear with me. This is our guinea pig run, complete with prowling neighbour's cat:
We've had the guinea pigs since they were babies, which means they've only ever known friendly life forms. So when they hear us, they rush to the wire (probably wanting food, but hey...) They have ZERO experience of predators, the only other furry creatures they've EVER seen are each other.
So they see this cat and quite happily go on grazing on the grass without a care in the world. For all the guinea pigs know, the cat is just another large furry friend. They have no concept of another creature that might want to tear them limb from limb.
So we see the cat sitting there each day, occasionally trying to pounce and coming up against the wire every time, all the while its intended prey just point blank ignores it! I suspect that this isn't a reaction a cat is used to getting!
Quite something, to live totally without fear, isn't it? The pets have no idea what fear or want or hurt or hunger is....