Yeah, but if it is properly programmed, like in the actual Pokémon games, they would be limited to 1 Mega-Evolution per battle and last till the end of the battle or if the Pokémon faint. I know that programming can be hard as I have studied in it, but everything CAN be done if one put his/her mind to it. Same for the HM Fly out of battle, you only allow the person to move to town he already seen/went to. And if their reason is that it will make the story too easy, well I could just do the same without Mega Evolution by grinding my Pokémon super crazy and that too will make the story 'too' easy. Its just unfair to have NPC use Mega Evolution when we can't cause if their Mega Evolution are not over powered then it means they have programmed them properly, so it should be the same for the one players use.
