Actually, Jessie and James never said they were superheroes in the first place. They chanted their motto and Cassandra assumed they were heroes. It's a case of mix-up similar to what happened in "We're No Angels" - the girl mistakes them for heroes when they chanted. I'm surprised that the dubbers remembered this episode when they dubbed "We're No Angels" and referred to it by having Kate cry "They're superheroes!" just like Cassandra assumed.
I hated this episode because that was when Charmeleon started acting mean. Charmeleon was only in three episodes(when it evolved, this episode, and two episodes later, when it evolved to Charizard). Of course, once Charizard trusted Ash in the Orange Isles, he quickly became one of my favorite Poke-characters and seeing him take on big stuff(like "The Symbol Life", where he kicked butt on an ARTICUNO, my fave Legendary Bird) shows how far he has come.
However, as one weirdo character in another anime said, "to make an omelet, you have to break a few eggs", and this episode was the first "egg" to break. The nice thing of this episode is that Meowth got a crush on a girl and did his hardest to help her Paras evolve. The part I hated most in this was the part where Charmeleon was about to KILL Paras and then it poked him and won. Deux ex machina, anyone?