Related Clues:

• Entry requirement, at times
• Security precaution
• Security requirement
• Check-cashing aid
• Entrance requirement, perhaps
• It may be checked in a security check
• Driver's license, e.g.
• Proof of who you are
• It's revealing
• Booze-buying need
• Proof of membership, maybe
• A bouncer might check it
• Proof of age, maybe
• Security checkpoint item
• Entrance need, perhaps