Not sure it makes much of a difference. Typically someone who wants to bring a gun into a stadium would have concealed one before this law took effect. Sure, there will be more guns there. But concealed carry licences aren't just something you walk up and get. The optimist in me wants to believe that those who bring a concealed carry into a stadium will conduct themselves as a responsible concealed carrier would. But the pessimist in me is also aware of the very real danger that could occur with just one drunk fan doing something stupid.
TLDR: hope someone with a concealed carry that feels the need to bring their gun into a football stadium will do so responsibly