I just ask at the lounge if anyone is seated beside me (or took the middle, etc), and if so, can they move me somewhere there isn't someone... I would say it's about a 90% success rate, except when the flight is exceptionally full...
I personally would prefer if SEs got their own seat, my sense of 'entitlement' is diminished in their presence (don't worry, I'm a 2010 E with 2009 SE tags still on my bag