There is almost NO risk of that happening, and whatever risk there is, is infinitesimal compared to the risk from these diseases. Children’s author Roald Dahl was a staunch anti-vax guy until his daughter died of measles.
http://www.people.com/article/roald-dahl-vaccine-measles-letter-daughter-olivia-death
There is still a risk of it happening, and since there IS one, you cannot justify forcing someone else to take a health risk, no matter how small YOU think it is.
I honestly don’t give a lick what Roald Dahl or any other celebrity or famous person thinks about vaccines. If someone wants to vaccinate, let them. If they don’t, then don’t. If a municipality passes laws that preclude unvaccinated from entering public facilities, like schools, I have no problem with that, as long as there are alternatives, like homeschooling.