Two multiple victim public shootings have taken place where guns were concealed handguns are allowed
Based on Jake's research it appears that I had one case classified incorrectly (the attack at the International House of Pancakes restaurant in Carson City, Nevada in 2011) so that there was a second case in the US where an attack occurred where guns weren't banned. What appears to have happened there is that one of the five who died was the killer himself and I don't count the death of the killer in my totals of those killed. Secondly, the fourth victim who died after the attack (the original story that I used was here (original post here)) and I hadn't gone back to double check on that case, as I admittedly should have done.
My statement on multiple victim public shootings should now read:
Since at least 1950, with two exceptions, all the multiple victim public shootings in the US in which more than three people have been killed have taken place where guns are banned. All the shootings in Europe since at least 1980 also fall into that pattern.