I can only speak for NZ where there is 50/50 spilt of relationship property and no spousal support. But I would think the intent of updating a prenup would be the same in NZ as it is in the US.
We updated our prenup to more accurately reflect our current asset base because the assets that we were each protecting as seperate property in the original prenup no longer existed. Original assets had been sold, new ones purchased together and our seperate assets had mingled, turning into relationship property. The value of each of our superannuation (retirement funds) had increased. We wanted to maintain protection of our super and inheritances if anything should happen before we made them part of the relationship property.
You can still protect yourself with an updated prenup but circumstances change over time, incomes change, assets change and in our case anyway, we felt the prenup no longer accurately represented our relationship.
If Alice was smart she would have pushed to have the prenup updated and removed the $750k deposit as Ioans seperate property. Luckily she didn't and the prenup stands. I guess it's a question for the legal people here if she had that option
@Hiraeth , do you have a view on this?