Old Neighbour

A few months ago this old lady and her humans moved into the house behind our place. She soon learned that there is always some tasty cat/hedgehog food to be found in our backyard so her humans put up a fence. between their lawn and our backyard. The old girl soon learned that she can still get her snacks if she waddles down their driveway and up ours but wouldn't actually do it too often - until about a week ago. Since then I see her almost every time I leave the house, and yesterday - when I made sure that she did go home after all - I noticed that my neighbours were not even at home. Apparently they leave the poor dog outside for hours (or even days?) on end even though the garden is not secure and the weather is getting cold and rainy. I am still trying to find the words to tell them politely that this is not okay.