Over at Polygon they have a run down of how easy it it was to sneak in to the LA Convention Center during E3 this year. The results aren't great. It also brings to question how hard would it be for someone to bring a weapon inside as bags aren't thoroughly checked.
Most security for LA Live and the LA Convention Center is handled by third party companies. For those who have experienced security in those areas they know they're quite bad at their jobs.
With Anime Expo on the way it opens questions of safety as who anyone who has seen these security companies before in action at AX would question how good they are as they hire teenagers and very old people to stop sneaking in.
Luckily the convention center is usually swimming in real cops checking out the area.
I consider most of the security for the LA Convention Center glorified ticket takers with no skills in an emergency.