Or maybe she really does have some kind of schedule conflict, or a family medical problem, and can't go but doesn't trust anyone else to do the presentation.

There may not be many people actually coming by a poster session but then a company can PR that they presented such-and-such results at this-or-that conference, rather than just having a yawn-fest PR that says "we got these results from some mice."

I need to be negative because every time I get my hopes up, the stock tanks. So:
this sucks, we won't have any results for a year or two, and besides that possum stew tastes horrible.