I think I know that guy Joe you used in your analogy Erad.
To date I have never had a problem titling a trailer as long as the signature on the back matches the name on the front and I don't recall ever furnishing a bill of sale. This may not be the case on a larger trailer with a higher sales value, I bought new
As far as a boat, which is not the case here, DNR asks for a bill of sale almost always.
As Erad said if it sounds fishy....