garbagemule
commented
10 years ago MobArena only detects if players leave the arena because there is a region specifically designed for checking point membership, both for arena players and for arena monsters, and that really isn't the solution. The spectator area must, by design, be closed off completely, because otherwise you'll see undefined behavior, when players leave the area and try to do other things. This is completely by design, and as such is a feature, not a bug.
If an arena (at least spectator zone) is not closed off, located high enough and the grounds beneath it is accessible by players, you can duplicate your XP (though slowly). So, when you enter the spectator mode on an arena, which can be jumped from, you can jump from it and crash down on the ground. You will drop your XP (well, a part of it), but when you leave the arena with /ma l, your XP is back, so that you can come back to the crash sight and collect your XP. So, you can quickly build up your XP without doing anything except typing in commands. So, what do I need to reproduce this bug: 0) Have some XP 1) Join an arena as a spectator 2) Jump down from that arena or die somehow else 3) Your XP will drop and you'll have 0 XP 4) Leave the mobarena with /ma l 5) Your XP is now back 6) Come down to death place 7) Collect your duplicated XP This could be really speed up if you set your home point just beneath arena. Possible fixes: 1) When someone joins an arena as a spectator, nullify his XP value (in the mobarena) OR 2) If a spectator (not only a participant) leaves the arena, return him to normal mode (force him leave the arena) because, as seen, it might be that detecting whether someone has left the arena is implemented/enabled only for the participants.