Legitimacy when it comes to leeching?

It is against the rules. I quote: "Exploit the Software, Cash Items or the Service for any commercial purpose, including the provision of "power leveling" services;" take from the Terms of Use on nexon.net.

4th job mages (or any job, for that matter) that let lower level jobs leech to help them train faster without them doing anything, but only providing mesos is a SERVICE. The 4th job mages are power leveling them, and according to that, it is against the rules.

By "commercial purposes" I think they refer almost explicitly to people who would be paying real world currency for someone to train their character, or allow them to leech. The act of leeching itself as was stated earlier in this thread is allowed. Providing mesos is no different than providing potions, or any other trade of in game items you could come up with (Other than NX, which is illegal).

I've never been a fan of letting others do the work for you. And I don't allow leechers in my parties. I get party requests from low level players all the time in the Ant Tunnel when they see my lvl 30 Spearman Slash Blast everything in her path. I'm all for partying up, but I would expect the party members to contribute, preferably by finding a spot on the map of their own to keep the spawns going. I mean, the whole purpose of the party system isn't for half the party to be AFK and still gain EXP, it was intended for gaining extra EXP than you would in the same amount of time by yourself because EVERYONE is working together.