Its a cute idea, but a bad one none the less.
You are spending one slot on a card that you need to luck into or you are forced to use resources to find it. Not to mention that as soon as you "fail" to find Garbodor, your ruse falls apart and your opponent will be on to you.
I think the waste of resources it could and does take, bench spot included, to pull off far outweigh any potential it has for, in the most extreme case , fooling your opponent so badly that they loose the game...
I played a game online where someone tried this on me. I'm running Darkrai/Hydregion, but when they failed to find Garbodor, I took it for what it was, a bluff and not a very convincing one at that...
If you want to do this bluff, don't actually bluff. Run a Garbodor as well.