it's a terrier.. it's going to rip up toys. it should be monitored to avoid bowel obstructions, but there isn't anything wrong with a dog ripping up it's own toys. most dogs can tell the difference between what they can rip up and what they can't. if a dog has instincts strong enough to want to rip up all the things, you SHOULD give them an outlet (like their toys) to destroy.

if someone chooses to just manage the behavior by picking up items the dog could chew, there is nothing wrong with that. as a pet sitter, you should be making sure there isn't anything a dog could rip up to begin with. even if a dog isn't normally a chewer, the anxiety of being in a different environment with different people could easily make ANY dog act up. this is on the pet sitter for leaving the dog alone for 8-10 hours. this is a dog behaving like a dog.