I can't speak for Rachel, but I'm cognizant that vaccination offers protection to my children, and protects others through herd immunity and it's for both of these reasons that we vaccinate our children. We don't live in a bubble...we travel frequently, and associate with people who travel frequently. Why do you think polio has been eradicated in the western world?
World travellers excepted, then.
Otherwise - I maintain my point. I do not think people who are aware that there are 0 polio cases in the USA, and that diptheria has many years with 0 cases, are vaccinating because they are afraid of their child catching the disease. They are doing it to prevent the disease from returning - which is a herd immunity issue.