Discussions

Maybe this is just a vent or a need for suggestions.  
 
What do you say to parents who brush off (or minimize) their children's 'contagious behaviour'? At a gathering our family recently attended, another child was licking whip cream off the un-cut cake while it was still on the counter! As politely as possible, I asked them to stop and the adults present just chorkled it off and laughed at how 'cute' it was. Another child walked around incessantly wiping their runny nose with their sleeve. One child coughed directly over my food. By the end of the day I was a nervous wreck ... but then again that doesn't take much nowadays. LMAO  
 
Anyways!  
 
I am frustrated at how they flippantly dismissed my concerns when catching these things. Maybe I am just more acutely aware and sensitive to such threatening situations because our family is constantly buying expensive medications to fight off unneccessary infections on a weekly basis. We have a toddler who was born 8 weeks premature. You would never know it now to see him (he is HUGE), but he does have a compromised immune system. If anyone so much as sneezes near him, he will have a cold within hours or days. He is a walking magnet for viruses. Just last week we battled a very precarious ear infection that revealed that our son is also allergic to penecillins.  
 
So, I get a little heated now when I see other children whose parents find it cute and unneccessary to address such inconsiderate behaviour. We have a family member who is at constant life-threatening risk to get sick and we are always careful to stay away when our son is sick as to not endanger their health further.  
 
For me, this issue is very difficult to address at large gatherings without simply leaving or avoiding the function alltogether.  
 
Today's society has so much awareness on germ control, hand washing and communicable diseases that it is impossible to plead innocent ignorance on this matter.  
 
How would you polite address such parents in a compelling manner? I need ideas.