A few people have had success in training their birds to accept a harness.
I guess it is a good idea if you would like to keep your bird unclipped but still want to take him/her outside. There are a couple of people in my town that walk around with their bird on their shoulder. I think the bird would be clipped though and they are not ringies but still, a bird none the less.
After training the bird to accept the harness, I think you would need to have the bird used to noisy areas of traffic, people and any other strange day to day things that might spook or stress your bird. It is one thing to have a bird used to harness but another to have a bird used to a totally different environment with strange sounds, sights and people.
Your bird may not be comfortable with all the hustle and bustle of shopping, no matter how much fun you think it is.
If you choose you want to teach your bird to go shopping with you, you could try taking him to a park or something similar where there are people but not like in a shopping centre. Get him used to changes slowly. This way you can see how he may react to different places and people.
