ls: why does -b insert backslashes before filenames' spaces?

[Paul Stoeber]

address@hidden:~$ touch 'a b c'
address@hidden:~$ ls -lb 'a b c'
-rw-r--r--    1 q        q               0 Jun 18 00:28 a\ b\ c
                                                         ^  ^
                                                         |  |
                                                         ?  ?
address@hidden:~$ 

This seems to be inconsistent with how -bR displays directory names:

address@hidden:~$ rm 'a b c'
address@hidden:~$ mkdir 'a b c'
address@hidden:~$ ls -lbR './a b c'
./a b c:
total 0
address@hidden:~$ 

It's also incompatible with Dired of Emacs 21.2.1.
This can be fixed in Emacs, but the backslashes look distracting
in a Dired buffer, so I'm biased to see the bug in `ls' first.

What would break if these backslashes were not printed?

They seem to be caused by the following fragment in fileutils-4.1/src/ls.c:

  if (get_quoting_style (filename_quoting_options) == escape_quoting_style)
    set_char_quoting (filename_quoting_options, ' ', 1);

I guess this was added as an afterthought, perhaps as a response to an
earlier bug report?