When I do a, as they are called in New Mexico, Improvement Location Report, the title information I use is what is provided by the title company.  If they don't provide it I don't know about it.  At a cost of between $300 and $400 it is not cost effective for me to spend a lot of time looking for documents.  The interesting thing for me is this, at least in New Mexico, the "Report" is prepared for the exclusive use of the lender and not for the buyer or seller.  We certify to either the mortage company, title company or the underwitter and to no one else.  It also states on our Report that the document is not to be relied on for any further improvment locations, like fences, and that no legal action can arise from what is shown on the document.  If I am hired to perform a boundary survey there is no limit to the level of research I do.
I have found that especialy easements are found in older documents that no one ever looks at.  In our area many old lumber companies acquired easements that are still valid even though the company is no long in existence.  Why?  Because the easement was usually granted to the owner of the company and does not contain any language to terminate the easement in the event the lumber company ceases to exist.  Or easements were granted for property in one county and recorded in the county in which the land owners resided, a different county, or there were easements created in a probate that was filed just about any place.  I probably do more than I need to but I consider that the owner usually hires me to let them know where there property is located and anything else that could affect their use.  Since no one else seems to be looking out for them I figured I would.  Call me foolish or call me nuts but that is just the way I am.  But your are correct, no one looks for old easements for a location report.  Again, that is why I look, no one else looks and not knowing does no one any good.