Uh... concealed is concealed, right? If they do determine you have a firearm, all they can do is ask you to leave the property. Failure to leave can result in a trespassing charge. As for the rent-a-cops asking to see a carry permit? Fat chance. And, I don't think I've ever seen any security at Tanglewood Mall.
Sounds to me like mall management is just making stuff up. How did this discussion come about, if I may ask?