I buy tickets for international travel on Delta (occasionally operated by a SkyTeam partner) and currently maintain Platinum Medallion status. I was upgraded three times on international segments in 2009:

JFK-TXL-JFK because the flight was oversold and SkyTeam Elite/Elite Plus were given "op ups" prior to boarding

JFK-BCN because the A line/purser was a friend of a friend and had prior knowledge I was on the flight.

Other times, I've introduced myself to the customer service agents, cockpit and inflight crew and not been moved up to business elite (nor did I expect it) but the flight attendants attempted to bring business elite to my economy seat (food, beverages, blankets, pillows, etc).