Cool, thanks for the information. I guess that means I'll need to go and remove Return on all the Pokemon I gave it to . I'll just modify Rock Climb and make it into a 102 power move and remove secondary effects to emulate it for the AI then. Kind of like giving them moves to emulate hidden power(like Flame Burst,Energy Ball, Bubblebeam etc.)
I've noticed the following things in my time playing with ai trainers, though not in battle subway:
The AI will do the same thing with other abilities similar to Flash Fire such as Sap Sipper, Lightningrod etc. Something cool about that is that if the AI have a Pokemon with one of these abilities and you use an attack of the same type on another one of their Pokemon weak to it they will switch in the immunity ability holder on the next turn assuming the Pokemon survives to predict you using it again and absorb the hit.
I think the AI may have been improved some from bw > bw2 as the AI no longer seems to use entry hazard moves on a Pokemon that has Magic Bounce unless it gets your hp low and it predicts you are going to switch.