its fine to help out in training a controller...PROVIDED YOU HAVE THE OPTION OF SAYING NO
I've been asked to accept an ASR approach to train a controller instead of an ILS...the wx was adequate, we backed up things with our onboard nav.
BUT WE HAD THE RIGHT TO SAY NO...ATC made that clear.
THIS situation didn't seem to have that. AND NOBODY, now a days with fuel costs so very high, WOULD DO IT.