Sophie is 8 1/2, and she was trained from an early age. However, I don't believe that when she poops in the house that it is an accident. The only time she is forgiven is when we have left her for several hours, and her stomach is upset. I believe that she just doesn't want to go outdoors sometimes. Especially when the grass is wet. We have one and two foot snow drifts out our back door, and she will run right out there an do her business, but one day-NO! Why most days and not another???
I have no idea. She just can be a stubborn little thing.