psql \watch always ignores \pset null

Hi,

>    /*
>     * Set up rendering options, in particular, disable the pager, because
>     * nobody wants to be prompted while watching the output of 'watch'.
>     */
>    myopt.nullPrint = NULL;
>    myopt.topt.pager = 0;

I found psql's \watch command always ignores \pset null setting.
The above source code comment explains why it does,
but I'd like to see the specified string for null value even in \watch's
output, in order to distinguish null and an empty value. Thought?
Is there any reason why \watch must ignore \pset null setting?

Regards,

-- 
Fujii Masao