Practicaly speaking, it's a waste of time and effort to make some sort of announcement everytime they do some work outside or everytime they put up barriers during large protests or such.

Do you want them to tell you every time they replace a toilet or paint hallways or move the POTUS to a more secure location in the event of a credible threat? Because that would be a few full time government jobs to do that.

And besides, would you believe them, anyway? If they had a notice up or tweeted that those barricades were standard privacy screens for landscape renovation, would you believe them?

So what would the point be, exactly?