Pet owners usually sign a waiver stating that any injury or illness a dog suffers while at daycare is the responsibility of the owner. However, most facilities carry liability insurance and pet business insurance in the event of a serious incident.
To prevent illness, facilities are strict about requiring proof of vaccination and general health from a veterinarian prior to accepting a dog. However, in an off-leash setting, scuffles or fights might occur. Reputable facilities will often hire vet assistants who can treat minor injuries and under-the-weather dogs. For anything more serious, a good daycare should make it a priority to get the dog to a vet, and get in immediate contact with the owner.