People complain about anything, I see.
As a tech support type and all-around computer geek, I have to say that deploying major changes on a Friday is a VERY bad idea -- staff taking the afternoon off, normal problems that don't get reported til that night, etc are all very good reasons to avoid late-week or weekend releases.
Besides, if you're superstitious, you won't want to release on a day that is renowned for its association with bad luck. (It is the date on which, originally, the Pope had all of the Knights Templar arrested en masse no matter where they were, all across Europe, although some claim that the superstition did not originate from that event.) The ill-fated "successful failure" Apollo -- you guessed it -- 13 launched at 13:13 hours, too ...
