Just wanted to say:
Now is not the time for speculation or blind legislation (blind because we don't even know the details, so anything passed now would have nothing to do with this and DEFINITELY wouldn't prevent another scenario like this). People right now are understandably emotional. People are angry, people are grieving. People are making knee jerk remarks before we even have the whole story.
Don't do that. Wait. Give people time to mourn the dead and heal. Then, a month or two down the line, you can start having that debate again. I'll be happy to participate.
PS: This really mostly only applies to the mainstream media, but also to social media to some extent- stop making mass killers famous. Stop publishing their names and photos and giving them exactly what they want.