I haven't seen any roaming cats in the neighborhood. Thank God! Because back in Illinois I fed many strays and some of my neighbors weren't pleased. Vetman and I also captured some and tried to find them new homes through his clinic. I never could understand why people let their cats out. In my mind it equates to letting a toddler out to roam the street. Ridiculous!
As far as dog poop, we haven't had any problem. I would say something to the person directly, if I saw it happening, but I guess that's no surprise!
I would only rat on people to the authorities as a last resort.