In order to prevent Distribution Services from sending emails containing empty reports in Strategy Developer, change the Distribution Services Error Handling as follows:

From now on if no data is returned for report, the report will not be delivered by Distribution Services.
The appropriate entry will be added to DSSErrors.log file indicating that the delivery is skipped due to no data returned.
2009-10-21 12:45:00.505+01:00 Distribution Service: MSIDeliveryEngine::Delivery: The report REPORTAME does not return any data. Skip delivery.