According to this, EA enlisted the services of a real-life mercenary called Richard "Woody" Mister to advise on dual-play shooter Army of Two, a man that both helped the publisher with details of the latest battle gear and customized weapons and had rather odd eating habits.
"He's crazy," said Reid Schneider, the game's producer. "He would put you in a hold," he said, demonstrating how Woody once grabbed his shoulder from behind. "You'd have bruises for weeks. We'd take him out to a restaurant and he'd never sit with his back to the door.''
Read the full thing through the link. It goes on to challenge EA on whether or not Army of Two might make someone want to become a gun for hire, which has to be worth a laugh.