Model help – sick visitors

Hi Brooke, we recently hosted some friends from overseas to stay with us for a few days. Right before they got on the flight here two of them were quite sick. This made me feel anxious because a couple of years ago we had visitors who arrived sick and their visit ended badly with our family all ill, baby in hospital and friendship ended. After doing models and discussing in my tutoring call I decided on these 2 models:

C visitors
T I have the right to ask them to reschedule if they are sick (we have important commitments next week)
F confidence, integrity
A ask them in a friendly way to reschedule if they are sick
R I was honest and expressed my real desire (can’t control their response)

C visitors are coming
T it is a real treat to see our friends
F happy and grateful
A cheerful
R I enjoy seeing our good friends

This worked well – I made the request, our friends said they were well and we welcomed them for a visit.

The problem was that our friends clearly were sick, they were feeling unwell and taking medication, one had been to hospital and nearly didn’t fly. After they left 2 of my kids quickly had similar symptoms, one is very sick. They are missing several special events and activities that are really important to them and we are all sad about it. My current model is:
C hosted visitors
T I tried to avoid it but this happened to us again
F victim
A worry about my kids and how to prevent this happening again
R angry and resentful (its happened again)

Something similar has happened several times. Now I want a boundary that friends and family do not come to stay when they know they have a serious infection. I tried to make a clear request this time and it didn’t work. Is there an option I’m missing, short of deciding not to have house guests at all? We want to make our friends welcome but not at the cost of our children’s health. This has been more severe illnesses like influenza and mycoplasma, not regular coughs and colds.