Vietnamese aviation authorities are asking carriers to slap a six-month flight ban on several passengers who have failed to pay fines for previous travel violations.

A statement from the Civil Aviation Administration of Vietnam named three passengers who have been “deliberately” avoiding their cash penalties.

Nguyen Thi Yen Linh, 28, and Mai Duc Lap, 40, were fined VND4 million (US$178) each for smoking on flights to southern Vietnam in July and have yet to pay up.

Do Tan Phat has also failed to pay a fine for his undisclosed failure to obey the crew’s safety instructions on a flight.

The administration last May imposed the six-month flight ban on a woman and fined her VND7.5 million ($334) for slapping an employee of budget carrier Vietjet following an argument over her hand baggage.