Most other areas that are controlled by other cartels don't bother innocents.
This attack happened in Monterrey which is the heart of their territory.
You would have to be crazy to go anywhere near there.
A buddy of mine who lives in Sinaloa, went to that area. He was scared to death and cut his trip short by 2 weeks.
In Sinaloa, things are under control, even though there is one of the biggest cartels there. They kill each other and there are very few problems with the killing of innocents randomly.