Q: I am helping small businesses with Google Places and noticed that most of them haven’t claimed their listing. The reason could probably be that they don’t know about it. If I am setting up their listing by adding photos, advertisements, reviews etc., am I taking the advantage of their ignorance to generate business, when they could have done it themselves?
A: After reading your question, I am assuming that you want to claim someone else’s listing and optimize it for yourself. This is a black hat SEO but you cannot claim somebody else’s Google+ Local listing because you don’t have a control on their phone or address. There are two ways of Google verification, one is telephonic and another is postal card. So, you cannot claim somebody else’s listing.
If you are saying that one business is helping others to claim & optimize their listings, it’s true. Since, Google has made the process easy for non-geeks; there are chances of a business helping other companies in navigating the Googleplex and learning to
1) Claim their business listings
2) Optimizing them for SEO purpose