My guinea pigs are fearless!! Barking dogs, curious kitties, loud noises like doors slamming, even vacuuming just feet from them doesn't phase them in the least! In fact, they purrrr when then they hear the dog's barking! I have found they aren't nearly as skittish as other small roddies, like hammies and gerbils. My dogs are curious, but after a look into their cage, they just walk away. And like Chloe's kitties, my cats LOVE the piggies. Oliver sits for hours next to the cage, purring away; the pigs and Oliver often go nose to nose through the cage bars and Oliver will even lick Moon!

And as long as the piggies have a safe place in their cage, like a timber hide away or " igloo" to escape to, I wouldn't worry about them being traumatized. But to be safe, I'd probably suggest to the piggie sitters that they keep them in a closed off area where the other animals can't get at them. You never know if someone might inadvertently leave the cage door open, or such.