If a Chaos Gym is in play, and I use a Poke-Power (let's say Mesprit LA's Psychic Bind for sake of example)...and my opponent plays TGI Power Spray, and my opponent flips tails for Chaos Gym...
Well from my understanding you will get to play power spray but it would have no effect. Also for you to use that card you must have 2 or more sp pokes on your side of the field.
I think DNA is saying what would happen if the opponent sprayed his Psychic Lock (and we'll assume, too, that all other requisites are met to play Power Spray).
I'm inclined to agree with capt.penguin: that flipping tails would result in discard without having any other effect.