I think Andrew was merely describing what he does and maybe he used the wrong nomenclature. I don't think Andrew is utilizing real estate brokerage in his wholesale deals. You want to be careful not to describe wholesaling as brokering, because any type of brokerage requires at least a real estate license.
Wholesaling in practice can appear very similar to brokering but again the difference is the wholesaler is utilizing an equitable interest in the property while a real estate broker/agent is utilizing agency laws.
Now Minna, net listings are not illegal in all states, but they are very touchy. You also could just charge a flat commission (i.e. $5,000 or $10,000 for a 30 or 60 day listing).
Also in Texas you not only have to disclose you are a realtor to a seller if you are buying their property, but you also have to disclose to them what the Fair Market Price is for their house, IF you came across them in your normal real estate agent duties (which is open to debate).
Either way being a licensed agent can be more of a liability than an asset when wholesaling. Not to say that you can't do it, but it requires more hoops to jump through to protect yourself.
I do think you can still fulfill your fiduciary duties to a seller in a wholesale situation by being open and frank with the seller.
i.e. Mr. Seller your house that you inherited from your parents is a piece of crap and I've gotten an As-Is offer for $50K that can close in 7 days. Now if you clean up your house, paint the inside and outside, put a new roof on it, and put new carpet in, I think we can get more like $90K sometime over the next 6 months or so. I know you don't have the $15,000 or $20,000 to fix it up and that you need the money now because your property taxes are behind and you can't keep a job, so my recommendation is to sell it now for the lower price.
I think you would still be fulfilling your fiduciary duties by doing something like this. You have informed them fully of the situation and are taking reasonable care to accomplish what they need and want. Now this definitely won't fall into a standard real estate brokered deal, but I don't think it has to bring any liability onto the agent for not fulfilling their fiduciary duties. Many agents won't even take the listings for wholesale type properties because they know they won't sell under the normal circumstances of most real estate deals.