This despite the fact that:
1. The head of the IMF in New York on personal business wouldn't be covered my diplomatic immunity anyway.
2. Diplomatic immunity does not protect you from prosecution for violent assaults or murders anyway.
3. Do you have any idea how many weirdo laws our diplomats and their family members would be charged with if the concept of diplomatic immunity didn't exist?
God, life is hard enough for diplomats and their families as it is and countries already hassle diplomats in weird ways. You don't want them to be hit with a cane for dropping gum on the sidewalk as well.
True story. I know a guy who was working as a diplomat at the U.S. embassy in Moscow. Every week or so he or his wife would come home and find that their furniture had been slightly re-arranged.
A couple of times they came home and found that someone had removed all the food from their fridge and replaced it with slightly different food - just to fuck with their heads.
Another time he was flying from Moscow to New York to visit family members. When he picked up his luggage at JFK he discovered that someone in Russia had removed all his stuff from his suitcase and replaced it with human excrement.
Can you imagine what they would have done to him if they could have just arrested him on weirdo criminal charges?