Then at your party shows up a neighbor who is getting over a case of the measles but is technically just passed the period of contagion. This person has also recently been exposed to shingles.
As the host, what do you do? Do you ask the neighbor to leave and explain the health issues of your family members? Do you sequester the family members in another room and serve them different food that the neighbor has not been near? Do nothing? Upon realizing that there were infants and elderly with compromised immune systems there, do you think the neighbor should have gracefully bowed out?