In 2022, flying from Manila to USA, the luggage-scanner people planted two 9mm bullets in my wife's suitcase. It was an almost brand new bag that had never come into contact with any guns or ammo.
I had read about this scam before. I argued a lot. They took us to the on-site police officer, who asked us a bunch of questions and then let us go. The whole ordeal lasted about 45 minutes.
I think they intended to plant the bullets in my bag, an American, rather than my Filipina wife's bag, so they could threaten me with jail time and extort me for money. I saw other people there that had their luggage shrink-wrapped prior to placing it on the conveyor belt for scanning. I will always do this in the future.
Also, Grab is good, but not as good as Uber or Lyft or whatever here in USA. Definitely use it, but I've had trouble sometimes finding a driver, even in Manila.