This must have been well coordinated with 20 techs all unplugging stuff at the same time. And yes, with my phone service now relying on cable, I would expect at least a knock on the door to let me know what was going on. Maybe not an adjustment, but some communication.
How the heck do you expect them to knock on the door? What if you were the one they were looking for?
And if they know enough to realize you're not the one and to knock on your door to let your know they're disconnecting your coax for 60 seconds, then they wouldn't need to disconnect it or knock on your door in the first place, now would they?
