Can I suggest that perhaps the reason Redpepper is having trouble with assigning the term "polyamory" to a poly-sex party is because of the societal need to lump everyone together under a general term, and that because the poly-sex concept is not one she would like to have associated with polyamory, which does technically mean "many loves", which does not necessarily mean sex?
For example, I was recently an avid homeschooler, and I still believe strongly in homeschooling. When people hear that you homeschool, they assume that your children are poorly socialized and isolated, i.e. stay home 24/7 and never play with children their own age, because this is what society says most often about homeschoolers. This is not normally the case, but is sadly true sometimes--rarely, from my experience, but only the radical neglect cases make the news. Now, if my homeschool support group one day involved the parents finding sitters and then meeting for group sex and the news got out to people who were inclined to stereotype, it's possible that soon everyone would be saying that homeschoolers were into orgies, though I doubt that stereotype would be true. (I will point out that it might be a refreshing change for some homeschoolers to stop hearing, "But what about socialization?" and start hearing, "But how will you get sitters for the orgies?")
By the same token, while some people who practice polyamory are into group sex and/or do not associate sex with emotional commitment, that is more about the individual than the practice of polyamory and perhaps should be more accurately called something else.
Or am I way off base?