I just want to say that, at a minimum, I am in complete agreement that Nexon should be more transparent about the odds of receiving certain prizes. A list of odds should be available for all events that provide random rewards.
For example: There are people who've spent thousands (yes, with an s) of dollars trying to get a Frenzy Totem from philosopher books with no luck. Let that sink in for a moment. At approximately 2,600NX per attempt, even just one thousand dollars [US] is about 385 attempts, two thousand would be 770 attempts. That's less than 0.0013% chance of receiving this particular prize, yet its one of the main prizes they list and use to sell philosopher books, full well knowing its so rare as to be nigh on impossible for most people to get, and some poor unsuspecting kids will look at the event listing and think they have a good chance to get the item, given how prominent the top tier prizes are listed in the event notes. If Nexon's target demographic is a younger audience then it could be seen as questionable to not provide some context when they display and use the top tier prizes to motivate selling cash shop items that provide random rewards (special hair styles included) when the chance of actually getting them is quite low.