Nerves (due to excitement and anxiety) can get the best of any dog, even if fully trained and have no accidents at home. Anytime you host a guest pet in your home, please be prepared. The guest pet is in a new place, with new people, sometimes, other pets and stimuli.
The best way to manage this is provide plenty of frequent walks/opportunities for bathroom relief outside In between, you could keep in a gated/playpen area on a more easily cleaned floor / potentially use a crate when can't be observed, and also use the leash as a tether to you (wherever you go, the dog goes, so you can watch for signs that the dog needs to go to bathroom).
It is Not responsible to keep a dog outside. If you're not prepared to care for the pet, let the pet parent and rover know. Rover will try to reassign to another sitter, but will likely take disciplinary action on your account (temporary suspension, non-payment for this stay if reassigned, changing position in search results, and closure of account are possibilities).
For future stays with other pets, you may have a better idea if it is a good match by discussing booking a 1 night stay first before booking a longer stay.
pretty standard
Nervous pups who have been trained for years have accidents upon arrival all the time. I take all of my boarders outside immediately upon arrival.
It can happen once when they’re new and nervous. Otherwise, it’s not “standard”- it’s ridiculous and you DON’T have to put up with it. We get paid very little, and certainly not enough to be making repairs. If they pee inside with me, they’re crated and sent home.