A mudallis may sometimes conceal an intermediary, making a report appear to be received directly from a teacher. Therefore, even an established meeting may not settle every ʿan narration from such a transmitter.
Discussing continuity does not make all “ʿan” formulae equivalent regardless of circumstance. Absence of tadlis, established contact, possibility of hearing, and evidence from parallel routes must be examined together.
For example, when two narrators are known to have met but the first practices tadlis in transmission from that teacher, his “ʿan” may require stronger evidence than a comparable report from a demonstrably non-mudallis narrator.