My opinion is this.. If you are wholesaling properties you are acting as a 3rd party real estate service provider (or solution provider, or consultant, or whatever..) So, you should have a license. Going through RE school and getting your license one of the only useful things that they really teach is ethics. They provide examples and show you how and why something is unethical and how to avoid it. Like for example even representing both sides of a transaction (which is what wholesalers typically do) and how that can be a sticky situation.
Now.. here is how I approach a motivated seller or any seller. I disclose I am a broker 1st.. (and also and investor) then I ask them if they want to get top dollar and list on market, pay a commission, go through inspections, possibly make repairs etc.. OR.. do you want cash right now, quick close, no commission, no inspections etc. I run quick numbers for them and let them know how either situation would work. I tell them my price would net you X amount. Or we could list at X price on the MLS and try to predict the net to them and Days on market.
The fact that I can present options, provide comps, and give them a bit of control I think puts them at ease and makes them want to work with me.
If I can get the deal, good. If I can get a listing thats also good. If I'm to busy to list it, I can kick it to another agent and take referral.
I feel like I can close a higher percentage of the leads that come through, pushing my advertising costs down and I don't have to make the redicoulus mark up that some wholesalers have to make because they spend 10k a month on mailers and ads and ditch 80% of the leads because the spread isn't big enough.
Also, if I do get the property under contract and the end buyers back out or fall through I make sure that I have the cash to actually buy it make sure it closes no matter what.
To me its just good business and makes it ethical. Give the seller all the info, treat them like a client. Do what you say you are going to do, put your money where your mouth is etc..