I do love GP's excitement about the energy potential of violent exothermic reaction upon contact with water ... and the proposal mere sentences later to ship industrial quantities thereof on creaky old ships
They have been quite common - they just aren’t typically in the middle of a major metro with 1000 cameras on them, because most governments aren’t that dysfunctional.
I’m not aware of anyone crazy enough to stockpile pure metallic sodium to anything like this scale. Here is the gov’t dumping a barrel of it in a lake though [https://youtu.be/HY7mTCMvpEM?si=aSJ2dPLrXsUuGOOJ].