So the initial concept (as I understood it) was to meter your confirmations relative to the magnitude of the transaction. Buying a cup of coffee ($3) could probably be a 0-conf transaction. But buying a lambo ($300,000) should probably wait 6 confirmations.
I guess this is a hard question to ask (since there won't be a record), but what's the most number of confirmations that have happened AND been reversed / double spent / orphaned?