So just did a couple of experiments...

sudo su -sh /home - returns permission denied errors on certain NAS subdirectories, but not a lot.

du -sh /home --summarize -returns the same errors.

du -sh --max-depth=0 - returns the same errors plus an error saying that using --max-depth=0 is the same as --summarize.

;-) for the purposes of what I was doing (creating a clip for posting) redirecting stderr to null was the best option.

But I learned a few things today, which is cool. ;-)