I am actually very pleased to have learned that snippet of useful information!

FYI when I wrote my comment I had just added an attribute to a product catalog that uses [very large number] - [product creation date in epoch format] so that I could have a latest added as the sort order without having to go through the bother of having DESC on my SQL query.

I assure you that only on HN could you find someone that is delighted to know about how 'unix time is not monotonic'... - thanks!