This is a good point. When I'm looking in a book, I will read the cover, authors' name, date of publication and topic covered, before delving into the index. Frequently when querying a database I just look for the individual or other information I'm interested. When using things like Ancestry and Family Search the search function is "figuring out" where you should go. As I was doing some research this weekend and found a WWII enlistment record for an ancestor, I did read the information concerning the particular database that contained the source record. It's a great idea to always document the source of the information we are including in our family trees or family databases.