Deere & Company (plaintiff) brought a trademark infringement action against FIMCO, Inc. (defendant) for using its green-and-yellow color scheme on farming equipment. During discovery, Deere hired an intellectual-property investigator as an expert to survey customers and prepare a report. The investigator took notes showing that customers inevitably finished the sentence “I assume yellow/green farm equipment is made by . . .” by saying “Deere” or “John Deere.” The notes also showed several salespeople said customers did not confuse Deere and FIMCO equipment. However, the expert report omitted those comments, so FIMCO wanted to use the notes as evidence at trial. Deere filed a pretrial motion to keep FIMCO from introducing the portion of the notes showing what salespeople said.