I cannot fathom that being a possibility.
Don't have even the slightest clue what actually happened, and I imagine we never will, so I suppose there is some ultra shady stuff that may have lead to her withdrawal. But I think it was just a really bad case of bad luck and she wasn't able to fly.
One does wonder, though, if it was a mild covid case as was reported, why LL didn't just give the presentation virtually which is what happened anyway.