That's what PM's are for.
That's what getting a service department job at a mercury dealer and becoming a student of mercury university is for
I have mercury university tech guidebooks going back to 2007. The vast majority of the information printed in the guidebooks is in the oem manuals, it's just a condensed, broad strokes version that focuses on commonly seen issues and any pertinent information regarding new products that information may not be readily available. Any additional info not printed but presented by the instructor is up to the student to record, usually in the form of notes. Often times this information proves very helpful in the field. Chatting with other students has pointed me in the right direction in the past as well
These days a majority of the information prior to any class is e mailed to the student prior to the class. Usually in the form of a windows slide show the instructor presents to the class either online or in person
Any printed information the student receives for an "in person" class is usually a workbook designed to guide them through the hands on portion of the class. Any notes/information the student records themselves is entirely up to them and again, usually prove handy when troubleshooting in the field.
It's valuable information that a mechanic has as a tool to perform their job efficiently. Whether it's illegal to share the information is unclear to me. I'm comfortable sharing my experience working on boats but when it comes to the notes I decided to record/worked for I feel I've earned the right to not share it with anyone if don't feel comfortable doing so