I was an ACO for 4 years (and hope to be again!!!), and we got calls regularly regarding pit bulls. Unless there was a valid concern like inadequate fencing, we didn't respond. And if we did, we didn't confiscate the dogs or anything. Unless we found an actual fighting pit with blood spatter, we didn't bother trying to persecute for dog fighting. I LOVED working there. Now, though, DE is trying to pass anti-tethering laws. FORGET that!
I did get called on a couple times while I worked there. One time, someone said I was training for fighting, because of my springpole. Next, the FIRE DEPARTMENT with their STUPID LOUD FIREWHISTLE that was right next door to us called in about my dogs barking at night. (They weren't) The people across the street called on me when they heard a foster great dane howling in his crate in the middle of the night. They thought I was beating him. (we were in bed sleeping!) And a couple calls about them not having water outside, because we kept it in the shed where it was cool, and not as dusty. Each time, they would call me laughing about the call. STUPID crap.
Anyway, it does depend on your A/C.. some really suck. Where I live now won't even respond to anything, really. And others are really strict, and out for a conviction.
I would recommend always keeping your rabies and licensing records on hand where your dogs are, and copies in your car. That solves SOOO many issues!