Inn System? what is this?

The point is, Nexon doesn't gain anything from forcing players not to play. Blizzard already has your monthly payment, they don't give a pomegranate whether or not you're actually in game. For Nexon, players not in game means that those players aren't being influenced by megaphones or their peers or sales or whatever, and thus are less likely to buy NX. In fact, there's the distinct possibility that in that 3-4 week period, they may find something else to do and never come back. That's really bad for them.

It's more about getting them to come back... if they log on and find a level worth of free double exp waiting, they're more likely to keep playing instead of just say hi to their friends and log out, which is what a lot of people do.