I think excessive use of tapes to "twitch" birds could harm birds, or
make them excessively aggitated - (male competitors, or angry,
uninvited other birds). Using a tape a little or immitating the bird, is
worthwhile though. Without sounding big-headed, I have called in a
Lesser Sooty Owl, owlet-nightjars and Powerful Owls, with my own
mimicry. It does help you see species. Recording of calls for the mallee
species at Round Hill, maybe pretty essential, as they're not exactly,
running about everywhere, when you're there. These more isolated species
probably don't get many people playing recordings of their calls, so I
doubt they would be harmed.
PS - If the only way to see a Blue Rock Thrush at Noosa, or a Paradise
Parrot on the Darling Downs, was through tape recordings, as they were
just too elusive, how may of you would use it??? I know I would!