I was unclear, or perhaps I misunderstood the comment I was replying to. I read it as "deploying on Fridays isn't a problem if you derisk the deploys".

My response was that you can't derisk deploys to the extent that Friday deployments are good practice.

Maybe you can’t derisk deploys on Friday, but we’ve derisked them just fine, and are eager to deploy more frequently Friday and every other day or the week - right now we do once per day, looking forward to continuous delivery to production.