The surge of countries implementing the requirement has prompted authorities to monitor forgery rings, one of which was busted last week.
According to the Associated Press, a group of seven were arrested for selling false tests at Paris's Charles de Gaulle Airport for between $245 – $492 to desperate passenger who had not had a check completed prior to arrival or departure.
The group of six men and one woman were charged with forgery and fraud, with each certificate stored on mobile phones and created at a medical lab in Paris.
In October, four tourists were arrested in Brazil for allegedly falsifying COVID-19 tests in a desperate bid to reach a luxurious beach destination.
The two men and two women were arrested on Thursday after landing in Fernando de Noronha off northern Brazil. The four travellers were accused of falsifying documents, using falsified documents and criminal association.
While it is becoming harder for travellers to fly around the world with a manipulated document, there has also been a case in England. According to the Lancashire Telegraph, one man allegedly doctored a friend's negative coronavirus test, printed it out and used it for international travel. The publication also reported another traveller was offered a fake document from their travel agent.
To combat the concern, some airlines – including United Airlines and Cathay Pacific Airways – have introduced specialised apps so that paswsengers can upload their coronavirus test results directly to their airline for verification when flying through some airports, such as passengers flying to or from New York, London, Hong Kong and Singapore.