PSZero is a DS game. There is an Action Replay for DS. Of course Action Replay works for Phantasy Star Zero.

So what, where's your problem with that? Jealous people can just get level 100 char with whatever equips the want instead of having to spend xxx hours grinding? Sad that you have nowhere to show off how good your character is from all your grinding?

Notice that there's a "Play with friends" multi-player function on PS0 and that both friends must've added each others friend code to play, which means that you most probably won't bump into someone using AR while playing like that. If someone is using AR, just remove him from your friend list instead of whining like a kid.

So unless if you're using matchmaking all the time, there's no problems. If you are using matchmaking, then just drop from the game if you join a game like that.