How does DupeBlocker handle records inserted via the Salesforce Mobile applications?
If the Account/Contact/Lead is created as a single insert then DupeBlocker will catch the duplicate. If blocking is enabled an error message will be returned to the mobile client.
However, if multiple records are created at once it will just create matching keys for them (any blocking, auto-merging/converting, duplicate warnings will not trigger). Multiple inserts are processed in batch mode and DupeBlocker only detects duplicates for SINGLE inserts.