Unfortunately, I can offer little better than a tautology as a response — most people simply see no need to do such a thing. Its presence is abnormal simply because of its widespread absence in the world at large. As such, we cannot decisively prove that this wasn't some mere quirk of Mr. Erickson's. It's circumstantial evidence at best, and can only be established to be so as part of the greater context of his work.

[The file with Mr. Condon's contacts contains about three dozen names with attendant contact information (or notes about unavailability of certain pieces of information) and listed relationship with Mr. Condon. About 60% of them are family members, but among those who aren't family, one name stands out: Goldie Gusse.]