Even without any drug, alcohol or kid involved, leaving your loaded gun unattended in a handbag is wack.
This wasn't even the first time her gun was fired in public through negligence, yet she's still carrying one around.
It is illegal to have a firearm on your person while under the influence of alcohol, even one drink. Now as to how often that gets enforced is entirely another problem.
But it sounds as if the problem was that she owned cannabis, not currently being under the influence. Imagine having some beer in your fridge and not being able to own a gun. I might have misunderstood that part though.