You can actually make a glitched mew look legit using ACE in RBY. You just have to tinker with the status of the mew in the code to make it work. I'm not sure if that's allowed though since you can't get mew anymore and it's unfair for newer players to not have one of the best pokemon in Gen 1 because of an event. There needs to be a way to get mew somehow without cheats and this is really the only way in the modern day.