Follow up post incase I was misunderstoood.
If Zeus shows the first sign of DA (hack up, growling, tail straight) then I will reassess my stance on taking him to dog friendly places such as a pet store. Like I stated before, I would never take him to a dog park or let him off his leash.
I would also point out that Zeus is neutered which helps in toning down AA and DA. It might be just me but it appears the majority of people on this site have pits that are not neutered (from all of the pictures I've seen here).
I am not naive in thinking Zeus would never harm a fly, but as of now his DA is nonexistent. Worst-case scenario he show signs of DA and I take him away on his leash. He's already had dozens of dogs show DA to him and he responds like he could care less.
Hopefully this explains my post more thoroughly.