I've seen several MLS wholesale deals get set-up, and sometimes wholesalers get into bidding wars on a property, so they have to buy it over list. However, at the same time they have it under contract on an inspection period, so the deal doesn't go off the MLS. An investor doing due diligence will see that it was purchased over list, but that does not mean that the investor can call up the seller and offer list even if the wholesaler dumps the deal. RE operates in a living market and the MLS only lists a suggested price at one point in time, not the current market value.
I know that there are a lot of "wholesalers" who don't know what they are doing, or are trying to make a killing on each deal. But that doesn't mean that every MLS deal that a wholesaler offers over list is a bad deal or that the wholesaler is an idiot.
If a wholesaler sends you a deal that looks strange or over priced, challenge them on the price and value. REI is all in the numbers. Just because it is on the MLS doesn't mean that the wholesaler didn't do any work to get the property. Maybe they have a vision for the property that you just haven't seen yet.