Steve Santner--- one of Michigans top birders! He's been here to my house to see the Carolina Wren we had and we see him at the Anchor Bay CBC get togethers'. Very knowledgable, responsible, and ethical guy. He knows Scott Jennex, Daryl, Allen Chartier etc. etc. & many more then I do.
BTW Calling Rails, Owls and other difficult species to find & ID with tapes CDs & the latest devices has always been accepted, even encouraged by various top & national wildlife orgs.---"If" done in moderation, discretion & for specific research purposes ---protocol much as it is for photographing birds & wildlife.--- Lately there is a small segment of birders who are annoyed or even against photographers "getting" pics of birds in any manner.
I don't know when this negative view of using audio callbacks came about but it didn't use to be that way for years & years.
Usually for these difficult species there is NO other way to know if they are around--(like the Atlasing projects). The ornithologists (scientists) know this.--Matter of fact for the counts, surveys etc. they have problems getting even a few people to do this. I can assure you the random occasional playback callings are NOT responsible for any declines in these species!