Possible Clues:

• Greets the Red Sox at Yankee Stadium, say
• Expresses disapproval of alcohol, say
• Disapproval sounds
• Performer's nightmare
• Ballpark chorus
• They might follow bad calls
• What villains may get to drink, so to speak
• Reacts to errors, maybe
• Expresses disapproval of alcoholic drink, say
• Disapproving fans' chorus