today I discovered some useless glitch to this glitch that will still get you a mew:creep:
after you battle the trainer and before you go to get mew, Buy 20 pokeballs(confirmed only to work on nugget bridge grass guy, and swimmer) and instead of the start menu popping up, this message will play:
With your ability,
you could become
a top leader in
TEAM ROCKET!
after the dialogue ends you will encounter mew