In a best case scenario, it's a used car dealership where the staff doesn't know what they're looking at.
And it's downhill from there depending on the store and/or staff.
Often, they only rely on the consignor, who may be as crooked as hell, or trying to unload a pile without facing buyers, or merely ignorant.
Some consigners may be honest, but just don't want to deal with a parade of clowns or low-ballers.
If a store is creating a false car, I would think some laws would apply; at least where a VIN denotes the model.
The appeal for some buyers is probably financing, if they don't know how to handle that themselves.
Bottom line: you have to know what you're looking at, and inspect it yourself, or hire someone for that.