interesting that you say that...
you are right for the most part, but slightly incorrect. It's gotten tamer for the kids but wilder for the adults.
Here in NYC, living in an apartment building, especially a big one, presents it's challenges to trick or treaters. First off, you cant go from building to building as for the most part, all buildings have security that does not allow visitors without authorization from the tenant through a buzzer system or doormen. Therefore trick-or-treating takes place only within your own building mostly (unless you go to a freind's building). Also, you cant just knock on anyone's door. Buildings have lists where you can sign up as a candy donor, and kids are not allowed to knock on anyone's door who is not on that list. On top of that.....kids are chaperoned 90% of the time. even within large luxury high-rises.
but parents have good reasons to be paranoid.
NYC turns into a playground for adults on halloween. at the parade in downtown manhattan, the streets are absolutely packed with revelers. most people are drunk. there is a great deal of drugs being used openly on the street. Every bar and club get packed to the brim. Every year, every holding cell in downtown manhattan also packed to the brim by the morning.
The fact that everyone is wearing a costume poses an advantage to criminals. they can wear a mask too, not be out of place, commit a crime and just take off their costume/mask or change it, and considering the crowds, it's very easy to get away with pretty much anything on halloween in NYC. The bad apples of society know this, and they take advantage of it.
My school would let out an hour early every year on halloween. That's because kids from the public school down the block - minority kids mostly bussed in from the ghetto - would try to mug anyone wearing our school's uniform. They would get away with it too - they just flipped their jackets inside out, put on different masks, and scattered. The next year they caught on and they were waiting for us an hour early, so the following year the school decided to cancel school on halloween every year.