I work in a hotel in Greece, father comes down to reception on Tuesday to tell me his son is vomiting and wants to know how to get a Dr. I explain the situation and tell him due to the extreme heat at the moment (44C in the shade) to not leave it too long as little ones go down fast when dehydrated in the heat.
Call out Dr and he has Gastroenteritis. Dr gives him injection for the V+D and rehydration medication and tells him to keep him in the room for 48 hours. Great.
Next day I see the father and he says son has perked up loads and points out where he is by the pool 
I asked him what the Dr said and when he told me about the 48 hours he says that its ok as he is better. I explain to him that its not just for his son to recover but also because he is contagious. The man just nods.
Next day daughter has come down with it and they are still by the pool.
Today mum has it, she has stayed in her room but kids are in the pool.
AIBU when I told him off a bit, saying you see how contagious it is and I hope that there are no newly pregnant people or other young people who get it from him being selfish.
He nods and walks off. I am now a little bit worried that he might write about me being "rude"
But my god how selfish, V+D and letting them in the pool. 