Deploying on Friday is fine if you can rollback quickly :)
Are you trolling?
I think the point was that you don't want to be messing with production when people are going to be gone for days. Even if it's easy to roll back I'd just as soon not deal with it. If your application is of such importance that rolling a change out Friday v. Monday makes a different in the business's bottom line, that business can almost certainly afford to have weekend staff that could cover it.