Metal detecting in a foreign country?

[SCUBA Dog]

In Cozumel, they did the red light / green light for everyone. A red light meant further inspection, but everyone had to put their luggage through the X-ray machine. Some, as in my case only had to put one or two bags through, while others had to put all of their luggage through. We flew into Cacun last year and I don't remember them using X-ray, unless it was done behind the scenes.