If I name my file or directory using the # (pound/hash) sign, SVN treats it as if it's commented out and ignores it.
(see more here, under Configuration and the Windows Registry)
How can I stop SVN from ignoring it?
If I create a file called #aaa# and run svn status. I expect to see #aaa# listed as untracked, but it's not displayed.
This is an OS issue.
Linux treats # (hash/pound) signs as special characters and therefore they are ignore. This doesn't happen in windows.
If you run svn add \#aaa#, it will be added to the tracked list and you can then see it if you run svn status.