As for security, many checkpoints allow you to pass with liquor in surplus of the normal amounts if you're on an international journey and it's still in the tam

As for security, many checkpoints allow you to pass with liquor in surplus of the normal amounts if you're on an international journey and it's still in the tamper-evident bag. Eg, from the TSA[0]: > You may carry duty free liquids in secure, tamper–evident bags, more than 3.4 oz or 100 ml in your carry-on bag if: > > * The duty free liquids were purchased internationally and you are traveling to the United States with a connecting flight. > * The liquids are packed in a transparent, secure, tamper-evident bag by the retailer and do not show signs of tampering when presented to TSA for screening. > * The original receipt for the liquids is present and the purchase was made within 48 hours. And the EU[1][^2]: > * EU duty free liquids which have been obtained at EU airports or on board of an aircraft of an EU carrier on condition that they are packed in packed in security tamper-evident bag (STEB), inside which proof of purchase at airside at that airport on that day is displayed, as recommended by International Civil Aviation Organization ; > * duty-free liquids purchased at certain airports in Croatia, Malaysia, Singapore or at international airports in Canada or the U.S on condition that they are packed in a STEB inside which satisfactory proof of purchase at airside at that airport within the preceding 36 hours is displayed. I don't believe the gate agent should have allowed the GP to keep the duty-free items (they should have been held until they were on their next flight). I would have found a member of the airline staff ASAP. And obviously, these don't cover all scenarios. They're likely fine for the vast majority of the travelling public. [0]: https://www.tsa.gov/travel/security-screening/liquids-rule https://www.tsa.gov/travel/security-screening/liquids-rule [1]: https://ec.europa.eu/transport/modes/air/security/aviation-security-policy/lags_en https://ec.europa.eu/transport/modes/air/security/aviation-s... [^2]: With flights directly from Australia now feasible, the second part of this section should probably be updated.