Possible Clues:

• "Stop gawking!"
• 'Be polite!,' in a way
• Parental admonition
• 'Take a picture, it'll last longer!'
• Admonition to the overly curious
• Caution to one who overlooks you?
• Earful for one getting an eyeful
• Kin of "It's rude to point!"
• Cousin of 'It's rude to point!'