I felt I had to add my bit to this topic......
18 months ago I caught chicken pox whilst working as cabin crew.
The outcome was, that as a child I had never had it and thus as an adult it was severe and very nasty I can assure you. I had 5 weeks off work, was not allowed to return to work until some of the scarring had disappeared so as not to frighten pax. Not only did I suffer the discomfort of suffering from chicken pox, but the 5 week sick leave affected my chances at promotion...and not to mention the permanent scars I am left with. And when I was suffering I had to be very careful around my parents as it could have triggered another onset of 'Shingles' in my mother .
So I would say that anyone who knowingly takes a child with chicken pox onboard an aircraft and thinks they have done well to keep it hidden is VERY IRRESPONSIBLE. Remember the knock on effect it has all round - not how you feel discriminated against from the airline.
PLEASE PLEASE PLEASE DONT DO IT - I would not anyone to suffer as I did.
PS: I Forgot to mention I was 36yrs old at the time!!! So it is not just a childhood disease