I always though the way the game handled evil teams was silly. They completely adhere to the rules of Pokemon battles, including never attacking the trainer and only holding 6 Pokemon and leaving you alone if you beat them. Luckily the manga and the anime to an extent fight this, with evil teams doing bad things because they're bad. :3
Never really paid much attention to it, to tell the truth. The only thing I really noticed was that their Pokemon were leveled around the same that yours would be and that always confused me because you want your plan to work so why send a bunch of people with level 10 Rattatas?