Just saying what happened to Phantasy Star happened because sega did a bad job at mod prevention in dreamcast that was never fixed. As a player from the dreamcast hacking and piracy was an major issue in the game and console. Also they left a lot of issues alone for a long time even after it was ported over. Duping and etc. was a thing they never fixed. Duping didn't even need actual modification to memory it was an issue with in game mechanics.
Though, the difference is for games that is mainly host base vs an mmorpg. In the case of an mmorpg, it's purposely causing chaos/grief. Host base games, as in co-op games or games you join lobbies then into a game.
