Umm. I'm completely baffled. I don't think you want anyone to answer to this. This is starting to get slightly unreal.What information do we have as players that our PCs don’t? [...] Everything we experience from that world, be it magic or monsters, we experience through our characters. So, by default they have just as much information as us. Perhaps more since they experienced this things first hand.
So with the same information as our PCs, the players called the body a fake. Not an illusion necessarily, but a fake. You can’t claim we were using out of character knowledge because out of character knowledge doesn’t exist in real life. You cant know something you don’t know.
I think I'm starting to bow out of this thread before it gets even more weird... (or I get booted by the moderators because I spell out what I think about this).