This is pretty standard for organizations that see a large portion of their revenue during those months. This is especially important for ecommerce-like shopping around the US holidays, for instance. Black Friday, Cyber Monday and every intervening day between Thanksgiving and Christmas and the New Year's holidays.

No daily/sprint code changes, release management, emergency approvals and the like. It works pretty well, no major outages and the site kept taking orders.

Source: worked on high-traffic e-commerce infrastructure around US Black Fridays/Cyber Monday shopping days.