What distinguishes an undocumented meeting from evidence of non-meeting?

Muʿanʿan Transmission: Possible Meeting, Evidence of Hearing, and Continuity

• The first proves non-meeting conclusively; the second merely raises doubt
• In the first evidence of meeting is unavailable; the second contains positive evidence of non-meeting
• The first establishes hearing, while the second cannot establish contemporaneity
• Both always establish the same disconnection; the distinction is terminological