Have all of the 5 families of New York killed innocent civilians by accident? I mean someone who is not a intended target by any means and is killed by accident. Or only some. For example when the Colombo war was going on and the one guy was killed in a shootout in a bagel store. And the Colombo boss who killed the nun by accident. Was this a common occurrence? I know it happens in other parts of the world.

most likely

You can't shoot people on busy city streets and not have a few stray bullets. I am sure every family did at one time or another.

http://www.fivefamiliesnyc.com/2012/04/list-of-casualties-from-colombo-family.html
https://www.dailymail.co.uk/news/article-2934102/NYC-pay-5M-kin-man-killed-Mafia-cops-case.html
https://nypost.com/2011/05/12/colombo-boss-feared-going-to-hell-after-nuns-murder-feds/
http://lcnbios.blogspot.com/search/label/demeo

Aug, 1972 - During the Second Colombo War, 4 innocent businessmen shot at while dining inside the Neapolitan Noodle Restaurant. Two of them died. The killer had confused them for Persico guys;
Apr 19, 1979 - Dominick Ragucci mistaken as Cuban hitman by Roy DeMeo.
On Jan. 4, 1982, fragments of a shotgun blast “penetrated the doors and walls of a residence” in Brooklyn, which resulted in the death of social worker Veronica Zuraw, who was also a former nun;
Dec 25,1986 - Nicholas Guido was showing off his new car outside his mother's home on Christmas Day 1986 when he was gunned down because he'd been mistaken for a mobster with the same name; (Nicholas Guido dead body)
Dec 9, 1991 - Matteo Speranza, a 18 year old innocent bagel store worker, was killed when Orena hitmen walked into the store looking for Tony Ferrara and Frank Guerra. The killer was Chris Liberatore (a colombo made man);