I have been informed that you can't trade Pokémon from Original Gen 1 and Original Gen 2 to Original Gen 3, so I am wondering how I can obtain a Mew in the Original Gen 3 games, even if it's through glitches. I really want a Mew, so I was wondering how to obtain one from Faraway Island as Gameshark Mew doesn't obey. That is, until I realized the Mew event ended quite a while ago. So, I wish to know how to get it, and if you can even.
Whilst there is no legitimate way to obtain a new Mew in original generation 3 carts any more, you can use either glitches or cheats to warp to Faraway Island and catch it in Emerald. The glitch method makes use of the Pomeg Berry glitch and is rather long and involved; full instructions are in this wiki how article: https://www.wikihow.com/Catch-Mew-in-Pok%C3%A9mon-Emerald
In terms of cheats, you should be able to use either Action Replay or Gameshark to warp to Faraway Island. (You can also use the cheats to spawn a Mew, but as you say, you need to carefully set the "fateful encounter" flag to ensure it will obey you). You can also use cheats to spawn the Old Sea Map item and run the entire event, but it seems that requires a few extra cheat codes to work properly. According to this site the Gameshark codes you require to warp to Faraway Island are:
D8BAE4D9 4864DCE5 A86CDBA5 19BA49B3 8DEB234A 4C8DC5EC
Another site mentions some other Gameshark codes that might work:
Alright, i found some codes. These are for the gameshark. Not the ar.
I tested these on a rom version of emerald- i'll be damned, they work. You must have the master and anti-dma codes on for it to work. The old sea map also needs the faraway enabler on.
Master code: D8bae4d9 4864dce5 A86cdba5 19ba49b3
Anti-dma: B2809e31 3cef5320 1c7b3231 b494738c
Replaces item in pc slot 1 with eon ticket: 121f112f da7e52b4
Replaces item in pc slot 1 with mystic ticket: 1901ddd1 aad31ead
Replaces item in pc slot 1 with aurora ticket: 667fc137 c4c35c38
Replaces item in pc slot 1 with old sea map: 16053ea7 b5ac6644
Southern island event enabler: 0d6a02aa b44948bd
Navel rock island enabler: 4465d861 df900be4
Faraway island & birth island enabler: C0443e89 7b97fec2 0976a51e fe4031b6