"Maplestory-event" scam

Or worse, this could also be a way that Meso selling sites get their mesos to sell.

I highly doubt meso sellers would be stupid enough to leave this up to chance like this. I mean that a meso seller has to depend on a steady supply to meet demand so it would make more sense to hack mesos (where you have a steady rate of mesos incomming) than to try to lure in the people with enough mesos to meet demands. True meso sellers could be using this to subsidize thieir constant influx from hacking but it'd be just plain moronic to depend solely on your chance at a "big score" with this scam...

and the way to report them is to email the hosting site via their customer support