I don't know whether dings are being sent.
Last week I attended the Ambassador Program at Sloan and talked with Harriet Barnett (from Admissions). The only thing she confirmed me was that during November ADCOM would read and grade all applications that Rod had sent them.
Then during mid-Deccember invitations would appear, to be conducted by January.
She didn't mention anything about dinging people during the process.
Anyway this was a 30 min conversation with her. During Rod's presentation in Brazil, he told the same story, without mentioning dings.
Hope this info had helped in anyway