In addition to the link you were given, a few comments.
1. Fanny packs are OK. I strongly recommend this for your wife so she can place her wallet and other true essentials such as her cell phone in it. Then turn it around so the bag is on her front side. This minimizes chances of pickpockets in crowds so thick physical contact is unavoidable. A cord that also ties the latches to your pants or waist eliminates grab and vanish after quick release buckles are opened. I never had problems at UT games but with the economy making people take chances they wouldn't have otherwise, well. . . .
2. I wouldn't bring a 3 year old. The steep steps at Neyland could could result in a fall with serious injury. The kid is small, in a large crowd it's too easy to suddenly lose that kid, he'd be out of your sight in less than a second. He could also end up being trampled, especially if a situation arises that calls for an emergency evacuation.
3. Based on my observations, Neyland is pretty kid friendly and fans tend to be sort of protective of kids in general. But I'd not put a kid that young in potential danger because many don't have the autonomy take defensive or remedying action if needed. Such as looking for an officer for assistance, if none seen, looking for a family with young kids for assistance instead of a single stranger, or going to a concession stand and letting them know he needs help.