AFTER I did my research on each person I checked out the online trees to see if I had missed anything. I was staggered by the very high degree of inaccuracy I found. I estimate over 90% of the trees had incorrect data for basic birth, marriage and death facts. Given that these people were unrelated, this was not just one "family historian" posting misinformation but many separate individuals.
On the plus side, 1% of the online trees led to gold dust such as family photographs or digital images of primary source material.