I have redirected this to pkgsrc-users because your query is about
pkgsrc not NetBSD proper.

  [ftp.netbsd.org EAR blurb including list of embargoed countries and
  those designated by the US as supporting terrorist activities.]

  I am from India.

  So inorder to avoid issues I normally use Non US websites to download
  Software.

Adding features to pkgsrc has a cost in terms of effort and maintenance
(even if patches are contributed by someone), and thus I think we need
to consider the relative benefits.

Could you explain what issues you are having and seeking to avoid?
India is not on the list of prohibited countries.

(I see that Iraq is listed by the ftp server, but is no longer
designated; I'll ask that this be fixed.  But presumably that's not the
essence of your question.)

  Is there any way to disable pkgsrc to download Software from sites
  located in countries such as US that restricts some forms of Software
  from being downloaded?

I don't believe that there is any such mechanism.  Adding it would
require some sort way to identify the set of sites the user wishes to
exclude.  This seems hard to do programmatically with high assurance.

  but don't want to play with mk.conf :-(

If such a mechanism were introduced, it would surely be off by default
(because the current situation is not broadly objectionable) and be
enabled by setting a variable in mk.conf.

-- 
    Greg Troxel <gdt@ir.bbn.com>