I agree with majority of your points. However, I disagrees with you on the below points.
While it may possible in a few cases/project(mostly repetitive ones) but with complex/custom tasks this is a disaster. I personally do not accept any work if a buyer provides vague and incomplete details on his/her project or they are in a bit hurry to just get the project started.
I personally don't want to, but I have to in certain situations. Sometimes buyers place an order for an airplane, even though the gig clearly states that the product is a car. To prevent any misunderstandings in such cases, many sellers choose to include the above phrase.
Many sellers also don't like to leave a negative review. I've personally never left a bad review, even though one time I had a buyer who ordered a custom software product without knowing how to install software on a computer, despite me providing a step-by-step PDF/video guide.