I have been reviewing some of the online pedigrees for my remote ancestors and I commonly see people added either without any source citations or where the locations cited do not match the places where the family lived. When we are confronted with a unified family tree program, such as the FamilySearch.org Family Tree where all of the registered users have access to edit and add content, we need to be extremely careful to examine the sources and conclusions derived from those sources.
Most of the errors I find in these online family trees are like trying to build a bridge in the air. You need to start with a firm foundation before you start building the bridge out in the middle of the stream. Here is a quote from the FamilySearch.org Family Tree about one of my ancestors.
This information recently came to light--mostly from *** (name of person deleted), and then using my brain and promptings to 'organize' that information into the families as they really were.This is what was provided rather than a source citation to any historical record. I really don't know how to respond to genealogy by "brain and promptings." I am certainly not discounting the importance of inspiration or insights, but they both usually come after a lot of hard work and research. In this particular case, no one has apparently reviewed even the records that are easily obtained and available. From my personal standpoint, I am still documenting this line starting with the previous or more recent generations. What is interesting about this comment is that the comment relates to a person who is not yet well documented from existing sources.
I would certainly agree that genealogy would be a lot easier if all I had to do was think about the families and not have to be bothered with all that messy and pesky documentation, but unfortunately, I am stuck with having done too many years of research to simply dump it all in the trash in exchange for good feelings and my "brain."
Genealogy should be source-centric. Every date and place should be supported by an evaluated and pertinent source document or record. As I have written many time before, unsupported entries in the FamilySearch.org Family Tree or any other compilation of genealogical data that is unsupported by valid sources is mere speculation.