Unix System V link

[Francois Bronsard]

I have a question about the dangers of having two hard links to the
same directory in Unix System V.  Basically, I cannot do a symbolic
link (because my version of the system is too old), so I was told that
I could use the system call link() to create a hard link to a directory.
However, I was warned that such a thing is dangerous since it might
confuse the file system (specifically, the programs find and
fsck/icheck/ncheck).  Now my question is : "How dangerous is it really?"
In particular, all I want to do create the following structure :
                    $home
                    / .. \ ...
                   /      \
                FILES      \   
                  \         \
                   \_______files
                            ...

 (The link between FILES and files is the new link that I want to have).
So what problems can such a link cause to the files systems?

Francois