That is, if we live in a simulation, which many smart people think is the most likely possibility…

Potentially, our simulation costs a lot to run. Which means they want it to succeed in whatever its mission is. It also means that if the simulation becomes stuck/broken and cannot be fixed, then they might choose to pull the plug.

One angle they could measure failure by is novelty. If too many changes start happening, they could conclude the result will become too off the rails. And Trump is making a lot of changes. He is making our world unstable. That could trigger something in the simulation software.

If they simply switched us off, we would never know. However, they might not want to waste the opportunity to see how we react to impending doom. So potentially the simulation will introduce a deadly asteroid, a worst-ever pandemic, a super-volcano, an alien invasion, zombies… And see what happens.

And that, to my reasoning, will be the proof we need.