This sounds exactly like the people I meet who walk daily along rivers and canals where every possible territory is occupied by Kingfishers, and sigh "I'd love to see a Kingfisher" at me - sometimes as one flashes past.....The many accounts of the birds being wary, from the 1800s to the 2000s, far outnumber the accounts of them being approachable. The quickest way to read about all this is Chris Haney's new book Woody's Last Laugh.
Unless you can quantify the numbers of observations of IBWO that are wary (and the skills of each observer) and the numbers where the birds are pretty much promiscuous (such as the one photographed sitting on the observer's hat) and the skills involved to achieve that, what you have are not data but meaningless anecdotes. But I expect you will have done that as part of your research.
At present the good evidence remains that they were not shy and the inference, that they are now not there.