If bans actually worked and guns were not available you would see more of this (warning–it’s very graphic!).
How fast can you draw and fire a shot? How much distance can an attacker cover in the same amount of time?
In answer to the first question 1.5 seconds is a reasonable estimate for most people. 21 feet is the answer to the second. Draw your conclusions and modify your behaviors appropriately.
That is one of the things the Navy drilled into Officers of the Deck and Petty Officers of the Watch concerning standing watch on the quarterdeck in-port – the importance of the 21 foot rule (especially considering how lots of people would not even consider deadly force, or the threat of deadly foce, at ranges of 20 feet or greater if the assailant did not have a firearm himself). Some deadly-force triangle situations are kind of hard to explain/imagine, but a few demonstrations of the Tueller drill (with Blue Force dummy-guns) more than drilled the point home for just about everyone at the training.
Between those pictures, and the pictures of that British girl who was attacked a few months back, though, even without a Tueller drill, people should get the idea.