Now before you say "HURP DERP WHY WOULD YOU ASK THAT STUPIDLY OBVIOUS QUESTION" I am just interested.
I've probably killed illidan 50+ times now, seen at least 5 glaives. Now I understand loot has a "pool" and each boss has multiple pools of loot (at least it worked this way in TBC) For example....the Skull Of Gul'dan and the Memento trinket could NOT drop at the same time as they shared (and still do share) a loot-pool. Now I am just wondering since the glaives are in a different pool, I wonder if the glaives are in a loot-pool together or if they're both in their own individual pool.
Now I have never seen both drop or seen anything legit on both dropping at once, but I've heard random stories online. Now I am just wondering if anyone can provide proof that both have actually dropped. I am 99.9% sure both glaives share the same loot-pool...so only one can drop at any given time, but I have an open mind and nothing is impossible (unless they do share a loot-pool like I am 99.9% sure they do)