Airline passengers who buy tickets online with credit cards that are not their own are usually required to have the card holder present when they check in, and have the card with them for verification.
This practice is implemented by three airlines The Straits Times spoke to - Singapore Airlines (SIA), Cathay Pacific and Jetstar Asia.
Unlike SIA and Cathay Pacific, which carry out the verification on all their flights, Jetstar Asia does the checks only on flights to and from Manila.
Cathay Pacific said the practice of physically verifying credit cards was implemented "more than 10 years ago".
A Jetstar Asia spokesman said: "For flights to and from Manila, every effort has been made to remind our passengers of the verification process. At the time of the booking, credit-card owners are notified of this requirement. This is also reflected in the itinerary and post- booking e-mail."
SIA spells out the condition on its website.
On June 11, Chinese national Chang Lihui threw a sign at an SIA ticketing employee after she failed to get a boarding pass at Changi Airport for a flight bought using a family member's credit card. The 33-year-old was sentenced to 24 days in jail on Monday.
At the time of the booking, credit-card owners are notified of this requirement. This is also reflected in the itinerary and post-booking e-mail.
A JETSTAR ASIA SPOKESMAN
An SIA spokesman said customers who are unable to present the physical credit card used for purchase in person may be required to sign a Letter of Indemnity, which can be done at any SIA ticket office or submitted online for verification. The purpose of signing the letter is to "minimise the risk of fraud", said the spokesman.
Cathay Pacific also said the verification is done "to safeguard the interest of the card holder".
In cases where the card holder is unable to be present at check-in, the airline allows for the verification of the card to be done at its office at Bugis Junction Towers. It does not accept an authorisation letter by the card holder.
There are exceptions to this.
Cathay Pacific said successful transactions made with its 3D Secure verification payment system - which adds an extra authentication step for online payments - are not subjected to the physical checks.
A spokesman said corporate flight bookings made by firms on behalf of employees are usually done using this system, removing the need for physical verification.
Said Ms Alicia Seah, director of public relations and communications at Dynasty Travel: "Flight tickets booked by authorised travel agents will be issued from a travel agency booking system, so passengers do not need to collect boarding passes or present credit cards at check-in."
She added that the travel agencies will verify the credit-card payment, if any, at their end. She said the same process applies to corporate travel agencies.
Between June 2015 and last year, about 400 people were arrested worldwide after being denied boarding or caught with tickets bought using stolen credit-card details, said the European Union's law enforcement agency, Europol.