I just love it when you have something like this, and they won't let you have scheduled downtime for such actions.
Though not in the £50k/hour area, I had a similar situation before Christmas... updates had been postponed to an internal system because "we can't take the system down". Updates postponed a second time because "X needs to do Y so you can't update yet", and so on.
There are only a few windows in the year where I can update without everyone whining, and every time "someone" different had to do "something" important and it was always something that I, or they, felt couldn't be left half-done when updates were applied (which included database schema updates of the databases they were using, etc.).
So it got to December. Where I had a three week holiday booked. And so I stated that the update NEEDS to happen. There was much wailing and gnashing of teeth but I got it scheduled in two days before I finished (I'm not an idiot! Never do updates on your last day in!). I got agreement from everyone, a bit of "Oh alright then", but it got scheduled in, and notified, and notified, and notified. And then a day before, someone kicked up a fuss because they realised that there was yet another "something" that couldn't ever possibly be done completely before or wait until after the updates. Of course, that's in their opinion.
Speeding up their schedule to get it done before the updates "wasn't an option" (despite the fact that they'd had MONTHS to do it in). Putting it off until after the updates "wasn't an option". Doing it while the updates were happening wasn't physically possible and certainly wasn't sensible.
I didn't even attend the meeting. I just sent an email saying "It's been postponed multiple times, while it wasn't critical, and now it's critical. I will be updating". There was uproar. Not least because someone then went and told *some* of the users that because of the updates the system would be down on the wrong day anyway (I suspected an attempt at sabotaging the update from happening). And obviously the other users had all been told that it would be down on the scheduled day.
It was then that the emails started getting personal, wondering why I was allowed to have holiday (because I'm human?!), why they were being taken over Christmas (because most of Christmas is compulsory holiday anyway, and there were never originally any updates scheduled for Christmas, and I wouldn't schedule updates over Christmas normally anyway? Literally triple/quadruple-postponements are the problem, not that your IT guy isn't working over Christmas when you do no business anyway), wondering why the works weren't scheduled in (they were), wondering why we had to schedule in downtime for updates at all (which would be a fair point, if it wasn't for the fact that the software in question can't be running on any client when you apply updates to the server, and all clients have to have the same version number as the database they use), wondering why we couldn't pick a "more appropriate time" (I did! Several times! And people not doing their job postponed it again each time!), wondering why "someone else" couldn't do the updates (erm... because it involved both Finance and HR data, so nobody else should be privy to that information, plus nobody else on staff is qualified to do so - or even close! - plus you don't listen to the guy who CAN do the updates, so you can literally go find a new IT guy if you let someone else touch that system / access / password).
Turned out... we did the updates... as originally scheduled... nobody was affected... I was there a few days to check it all went okay... everything was fine... nobody (not even the users) shouted. A lot of fuss over nothing.
And now I can look forward to a discussion about "Scheduling all future updates". Which I do anyway. But now it will always mean "making sure my original schedule lets me throw people off the system", not just polite announcements. Because my schedule takes into account far more than their last-minute "I haven't been doing my job" reasoning ever does. So I checked the calendar for 2019 for when the system can go down. It looks like I have maybe a day in a week in March. And a few windows in July. Let's hope that a) no critical update is required, say for the new financial year or Brexit, b) not one user "has to" need the system in those windows, c) when I schedule it, people don't suddenly remember that ultra-urgent thing that they've put off all year must be done in that day because they're too lazy to do it before then.
Putting off the updates for every whim basically now means that you don't get the option to put off the updates. Ever.
To say that making a fuss over such a non-event was counter-productive isn't the half of it.