My dad is blind. The owners do have a social responsibility to pick it up. However all guide dogs are trained to step into the kerb edge to shít. My dad picks it up - he instintively knows where the dog has crouched. Blind people however cannot be prosecuted for not picking it up! /poo
"all assistance dogs are trained to poo on command" that's genius! Could lead to problems if the command sounds very like "Sit!"