6:01 vs 7:01

I am curious, how did they come up with 7pm on Friday, as a date when emergency state should be lifted? I know that you need to set some kind of cut-off date, and almost all of them would seem quite arbitrary. Would it not be a bit more realistic to say midnight? You know, you wake up in the morning and say, "what a nice day, it's better than yesterday". Otherwise, you get "well, I am safer now that a minute ago..."