Can you edit the information in the FamilySearch Family Tree when adding sources?

Lately, FamilySearch.org has been adding videos to their YouTube.com Channel that address very specific issues with the Family Tree and other questions about family history research. This video features Robert Kehrer discussing one of the specific issues when adding sources to the Family Tree. Apparently, they are working on a way to edit the information in the Family Tree at the time a source is added. If you are familiar with other online database programs, you might be aware that at the time you enter a source, some of the programs allow you to "update" or replace the existing information with the new information from the source. This seems to be good idea, but Robert points out that the existing information may be more accurate and the system of allowing the record to be updated needs to provide the basis for the existing information so the sources can be compared. Of course, this is not a problem if there are no previous sources.