Unfortunately, I don't think you'll find a solution by asking this question here. The folks who are making the mistake you're asking about do so out of ignorance when they don't capture the family name headstone and link to the surrounding stones. However, the other issue is that not all volunteers have the same intuition. By this I mean that I've taken over 25,000 photos and sometimes the stones look alike and the names are the same, but other times, I don't link them because it's not apparent that there's a relationship.
At the end of the day, the getting started tutorial briefly covers linking family name headstones, but not the myriad of other situations.