The thing is... mall floor plans are public information. Because the mall proprietors want you to go there and spend money... And people who have mobility issues are more likely to go spend money if they can plan a nice problem free shopping excursion. So you can pretty much google up the floor plan to any shopping mall you want.
Scouting a shopping mall can be done without getting out of your computer chair. Shopping malls, sports venues, the whole "Casing the joint" thing is Hollywood BS. Only really applicable to a robbery when you want to figure out when there are as few people as possible. Whereas if you were going to shoot up a shopping mall you'd want to know when the most people are going to be there... Early afternoon on a Saturday, duh.
And of course you don't think there's government officials working on this shit?
Here's what I can tell you: North American governments have already identified the area of potential vulnerability in which the next 9/11 scale terrorist attack in North America will be played off of. I'm not going to tell you how I know that, just in case terrists be reading this. I'm sure the news already published it somewhere anyway.