Darren,
George could speak to your questions much better than I can but from what I know, Winnie wasn't really unwilling to participate so much as she was hindered by preferences. By that I mean that she wouldn't fly at all (nor go near water) and by the time it became a big deal to have groups of survivors at conventions she was already in her mid-80's and didn't want to make long trips by land. She told me that she didn't mind talking about Titanic at all and proved it during the time I spent with her. At the same time she didn't mind talking about it, neither did she actively seek to talk about it. I think she lived a lot of years in which Titanic was only a footnote to her life and she sort of kept it that way. One thing that really stuck out was how matter-of-fact she was when talking about her own experience. When I asked her if she was afraid for her life, she almost spoke comically of how she was more afraid of having a lifebelt put on than of getting into a lifeboat. She thought for sure that getting the lifebelt put on meant that someone was going to throw her in the water. When discussing her experience in the lifeboat, she matter-of-factly stated that a German woman pulled her dress up over her and she got warm and fell asleep--end of story. She didn't particularly like to sign autographs nor have her photo made and those small personal preferences may have made her shy away from big gatherings too. George and others can speak to all this much better than I can as they knew her intimately all thru the years--but these are my small observations, some of them backed up by things I've been told by those that knew her best.
Phil