My copy is at home, as is my co-worker's copy. Hopefully I'm not saying something fundamentally stupid here.

Perhaps the solution to this entire muddle is to have as the first line of commentary after that best practice read:
Allowing the same name ensures your program will operate correctly when users, inevitably, do specify the same filename. Be Prepared, as the teach Boy Scouts 1.

1 If you have trouble remembering the Scout's famous motto, seek out the Tom Lehrer recording and have that song play through your head while coding.