Wow, somebody was given both best master and best in show? Ouch. No wonder there was a flame war.
Usually where I judge and/or compete, if you're in the running or have clinched Best in Show, you're automatically out of the running for any other major awards - there's no need for a best in class on top of it. It's possible for a Best in Show group at some cons to also get an HM for performance or a joke award, or crowd favorite, something cute like that, but that's not as upsetting to people generally as winning multiple major awards. Which, really, is something to take up with the cosplay staff/director or judges if that happens.
Founder and President, Madison Area Costuming Society, a chapter of the International Costumer's Guild
Strange Land Costuming - www.strangelandcostumes.com