Interesting read on a Plumbers Forum on the subject.
Good argument for air gaps Marcel.
I do see them as in yesterdays job, but not often enough that I think many care.
Might as well yell into the wind .
It is code in Chicago, but never enforced apparently.
There was not a good argument at all for an air gap, just an argument. 
This quoted post sums is up quite nicely.
Brian reading only the parts that support you does not count.
"A high loop doesn’t do much to protect us from syphoning. "
That is the reason for air gap requirement.
Bacterial infection is not fun.:mad:
Spent 5 days in a hospital with it, from a restaurant once.