Online searches.....or indexed searchs from hard copy books...whatever they may be are quite simply as accurate as the human being who input the information.  I worked for a few years at a title company where we hand indexed the data into legal description indexes; maintaining our own set of books. I wager to say  that you could walk into any Recorder of Deeds office in this entire country and not a single one would give you a warranty that the information contained therein is 100% accurate. 

Ellen