[paraph1n]

> The outcome provably does not exist until you measure it.

This is not true. It only provably does not exist in local hidden variables.

[red75prime]

It doesn't change much in practice. If the event is influenced by a state outside of its past light cone, you (that is observer inside the universe) cannot predict the outcome even theoretically.

[Dylan16807]

I believe "in practice, theoretically" simplifies to "theoretically".

In actual practice there might as well be hidden local variables here. You wouldn't be able to tell the difference, even though you could in theory.