I'd have to agree that you can definitely play "live" vs. other people. I doubt the AI is designed to just give up if things start going against it, whereas for a player just refresh and match against somebody else if the fight looks hard. When half way through the enemy simply stops deploying anything, I'd have to say it's probably a player.

That said, I don't think I've had a fight yet where the opponent plopped immediately, but I tend to be impatient and do so all the time. Fights don't take energy, so if you lose, whatever. I'm not convinced how well you do even affects the pack you get, and you only get 5 victories every several hours... Or days... just got a pack that's 96 energy to open. That's what, 1 day? (think it was a 1 star to 0 star time out victory) So just bang out victories fast and move on.