Earlier quoted context omitted.
Don’t be silly, if customers were unhappy about the lack of service on Friday, they will let you know between Monday and Thursday.
This assumes customers would want to return three days later just to tell you that a problem happened last week. Most people do not do this, especially if they can make it work on Monday. Nearly every time that I experience a problem on a website, I try to report the bug / customer experience. And nearly every single time, if it's even possible for me to report it at all, it takes me 30+ minutes just to figure out ho…
The idea that literally no customers would give you negative feedback about being closed one day purely because they could not be bothered to call in another day simply does not pass the sniff test.