Like all businesses, you can't stop word of mouth if it is an opinion of a previous consumer. 5LM, don't worry about the chatty family, it is doubtful it will have no real impact on your business. Most people smile and nod (and ignore) because they have no investment in the story. People are naturally self-focused.

Amanda's policy is well written. I would feel comfort reading that in a contract as it reads to protect the family and ensures that there is no expectation of a reference to a future caregiver.

As for the curiosity of what you are getting, from all I have read what happens at one caregiver is not necessarily what is going to happen at the next one. So a reference either way is a bit misleading since you may be the shining star for one kid that was the dreaded one for another.