Yellow book was used for decades?
Well, but this yellow book was only needed to enter certain exotic countries. But Covid19 changed it all.
There are many people in the EU who refuse to get vaccinated, but still want to travel to the Med.
I don't know if there were sanctions for using it with fraudulent info.
Obviously they can't check them all.
You can buy a blank yellow for EUR 1 or EUR 2 a piece. Then you just need a forged stamp and a sticky label printer (for the vaccine charge number). That's it. There'll be a market for forged yellow books.
But it's not like people are going to spend hundreds or thousands just to fly somewhere so they can use fraudulent vaccine info.
No, it's the cheap Mallorca package holidaymaker, who believes in conspiracies and cheap travel ...