The merge engine is terrible

 Lately I've been getting quite a few merge messages.  A bunch came from my cousin, who has not been exercising any care and attention in entering information in his version of the family tree.  Consequently, I'm seeing these very sloppily entered names - some spelling mistakes, no capitalization.  When I agree (reluctantly) to a merge, guess which information is being accepted?  So now all the hard work I put into the tree is buggered up because of his sloppy work.  What criteria is used to decide which version is correct?  The idea that they want me to pay for this quality of of implementation is laughable.