When a visually impaired person?

The handler is taught how to do this. The dogs are on a strict feeding and relieving schedule, which is adhered to wherever they are. The dogs are relieved at the same time every day beginning when they are pups, and continuing through to when the handler is taught the dogs' schedule at team training.

When a dog defecates, it takes a certain "stance". The handler is taught how to recognize this stance during relieving time at the school they attend that is provided by the organization which provides the Guide dog. The handler is taught to put a "doggie bag" on their hand, run their hand down the back of the dog to where the "deposit" is, feel around for something warm and squishy.....and scoop it up in the bag. They then turn the bag inside-out, tie the top and place in the nearest trash can. Simple.

I used to have a woman neighbor who was blind. She could tell when her dog dropped a load. She would cover her hand with plastic then search around until she found the load. I have no idea what she did after that.

I just think that maybe the dog is either trained to hold it in until a convenient time or to pick a convenient spot that no one ever has to know about.. >:)