[CentOS] vsFTPd and hidden files - standards compliant?

Hi Folks,
I recently received a complaint regarding the vsFTP server I'm running 
on a CentOS 4.x box. The complaint was that it is improperly responding 
to the LIST command - it is not returning hidden (period prefixed) files 
in the directory listing.

I investigated and found that vsFTPd would only return hidden files in 
the directory listing when it received the command "LIST -a". Reading 
RFC 959, it appears that the LIST command does not officially support 
any flags.

I found the "force_dot_files" directive in the vsFTPd config file. 
Enabling the directive appears make vsFTPd RFC compliant with regards to 
responding to LIST -- returning all files and directories (even "dot 
files").

So I guess my question is: can anyone confirm that "LIST -a" really is 
contrary to the RFC? If so, does anyone know why $upstream_vendor would 
ship a default conf file that is standards non-compliant? Is there 
something I'm missing here?

Thanks,
Andy Hull