I asked this question at another brand of family tree program.
The following is a reply on the subject and opens some other worms.
[quote]There was a lot of discussion about the shared facts during the development. One issue brought up was if you share an fact with a person who isn't in the Family File, then that person isn't added to the file and isn't searchable. Which begged the question.... do you add a new unlinked individual to select that person as the witness, thinking that maybe someday your paths will cross with another researcher based on that individual?
Or do you just add that person as a witness without adding him to the file, and who will be "lost" in the file as far as searching on that individual? The name is stored in a field in a table, but the programmers haven't made it searchable at this time.