A number of years ago I was on a sailboat that put in at one of the nice yacht clubs in Miami. Don't remember the name. I was directed to go down the road about a half mile to buy beer at way less than yacht club prices. Nice street, at night, well lit, but when I got to the store all the goods and the working people were behind bullet proof glass, and the two customers were covered with tattoos and filled with attitude. Got my beer, kept my hand on my pocket knife, and made it back to the boat with no problem.
As in any big city, stay aware.