My rule is simple: if a seller blocks ordinary verification, a no-match result would not persuade me to continue. The search only speaks to records checked at a particular time. It cannot explain away evasive behavior.
A seller's conduct is separate evidence
Refusing a physical serial check, changing the story, demanding unusual payment, or asking you to ignore a document mismatch are reasons to pause. None alone proves a crime, but buyers do not need proof of wrongdoing to decline a deal.
Check whether the search was meaningful
Confirm that the search used the watch's actual serial, note its date, and read its source coverage. A screenshot supplied by the seller may not show the full input or terms, so ask for a transparent process.
Use a clear stopping rule
If you cannot independently verify the watch and seller before payment, walk away. You do not have to resolve every inconsistency yourself or accept the seller's deadline.
The right purchase can survive reasonable questions. If it cannot, there will be another watch.
Verify the Exact Watch
Run your own dated search after confirming the serial on the piece.