would I have to say..."oh you revealed. bear strength? well that's my face down enchantment on your creature,let me go ahead and destroy that now that you have one revealed?
Thats how I interpterated it, except the revealed one is destroyed not the hidden one.
to re quote: "There is no limit to the number of different enchantments that can be on an object, but each object or zone cannot have more than one enchantment with the same name attached to it at one time. This includes both hidden and revealed enchantments. It is possible both players may attach an identical enchantment to the same target. if an identical enchantment is revealed on the same target, it is immediately destroyed."
My reading and interpretation was:
To use the Poison Blood example-
I play Poison Blood facedown on myself, obviously with no intent to reveal it...but because I suspect the opponent will try to use it on me.
Now, Poison Blood is not a legal target for me to play on myself again because of the quoted rule. no copies are allowed, face up or down. But, because the rule says "its possible both players may attach identical enchantments to the same target" So my opponent could still play a Poison Blood face down on me (since the opponent doesnt know better)
Once the opponent reveals HIS Poison Blood, it is tagged as identical to the facedown one I have. Which then obligates me to inform you that the Poison Blood you flipped must be destroyed because I already have a copy of that spell attached to me. Because the rule also states: "if an identical enchantment is revealed on the same target, it is immediately destroyed". The revealed one is destroyed. So because my opponents was the one revealed, and it is identical to the unrevealed one it must be destroyed an my unrevealed one stays there though its identity is no longer a mystery.
Or, in a reverse scenario of using it to deny a beneficial enchantment:
We are both Force Masters.
I play my Forcefield Face-Down on you.
You can still attach Forcefield to yourself (and do so, for this example) and I couldnt play another on you.
When you reveal Forcefield, I inform you that you already have that enchantment on you and then you must destroy it. (and show the card or call a judge I assume to confirm)
Then I use Shift Enchantment to get my Forcefield back.
That is how we thought the rule was stated, making Enchantments interesting ways to counter themselves. But we were never 100% certain if that is how it was meant to work.