@Bastett It happened one time in Russia in 1907.
At first things looked normal, except that only one house in the Tunguska region got presents, then 6 months later all the rest of the quantum-displaced presents tunneled through to that little house all at once.

So, whatever you do, do not observe Santa.

@androcat @Bastett There both was and wasn’t a sighting of Santa in 1974 in Darwin, Australia too. A girl named Tracy both spotted and didn’t spot him. There was more danger this time, because there were nearly 50,000 people living in the impact zone.

Santa, acting in desperation but having learned from the 1907 incident, was able to reduce the impact massively by making up a story on the spot and having her believe that all she saw was the wind blowing; Tracy has spent the rest of her life thus far in a superposition of having seen him and not having seen him. Sadly, the results were still catastrophic, with 66 lives lost, many injuries, and about 80% of the houses etc. destroyed, but still there was far less physical impact than with the previous event.

Racked by guilt, Santa has also been working hard ever since on further reducing the likelihood of further sightings (eg: Naughty list), and their potential impact, but further details are secret.