He who is harry newton said on Fri, 6 Oct 2017 12:03:29 +0000 (UTC):

Add a black box over the desired redaction area:
View Filters Add a Filter Show Video Filters Text

When using Shotcut, watch out for this editing anomaly!
http://wetakepic.com/images/2017/10/09/shotcut1.jpg

The oddest anomaly happened while using Shotcut which is completly
unintuitive, but it threw me for a loop for a couple of days (elapsed time
as I was working on other projects), so I don't want others to get stuck
with this Shotcut-specific export problem.

I found the solution he
https://www.reddit.com/r/shotcut/comments/6tajpo/my_text_filters_dont_show_up_in_exported_video/

The problem was that the video was greatly edited such that it played
perfectly in shotcut, with all the sensitive information (which Android
reports a *lot* of) blanked out - but - when exported - there were no
errors - but - the areas were NOT blanked out!

Huh?

It turns out that the one character you can *not* use to blank out text
areas is the "space" character!

You can use *any* other character - e.g., underline, dash, x, whatever ...
as long as it's not the space character - then the areas you blanked out
inside the editor will *also* be blanked out in the final video output!

Who knew?
Not me.

I know now.
So do you.
http://wetakepic.com/images/2017/10/09/shotcut1.jpg

Now that this oddity is solved, my next hurdle will be to find a
no-registration web site that will upload a 5-minute 50 MB MP4 video.