Wouldn't that mean you need a ref link on everything?

I'm still confused why you would target only the Mabi Coin page for reference tagging. Does the information on the contents of the 7th Anniversary Gift Boxes not also originate from a Nexon-created source? What about the details of the Lunar Fortune Event? Or the prizes from the Celebrate St. Patrick's Day Event (2015)?

It's already understood that aside from the templates and coding and some user page fan art, the editors of the wiki own absolutely none of the information that we've documented, that the entirety of the site is already copyrighted by Nexon. With that in mind, we use reference tags to denote what text is a direct quote from Nexon-published announcements, and what text is a rewording by wiki users.

The information on the Mabi Coins page that you insist of reference tagging reads

• 7th Anniversary Rock Paper Scissors Event 5 Coins (Play 20 games total), 10 Coins (Play 100 games total), 10 Coins (Play 200 games total), 15 Coins (Play 300 games total)
• Mabinogi 7th Anniversary Event Quest: 1 Coin (one time only)
• The Suspicious Milletian Quest: 5 Coins (one time only)
• Hello Fellow Quest: 5 Coins (one time only)
• The Fattening (Daily Event Quest): 1 Coin (once per day)
• Roulette Game (Daily Event Quest): 1 Coin (once per day)
• Hammer Game (Daily Event Quest): 1 Coin (once per day)
• Sitting in front of any campfire within the event area for 10 minutes: 1 Coin (once per day)

while the event announcement text reads

Titles with Mabi Coins

• Play 20 Rock, Paper, Scissor matches:
  • Title: Rock Paper Scissors Beginner
  • 5 Mabi Coins
• Play 100 Rock, Paper, Scissor matches:
  • Title: Rock Paper Scissors Novice
  • 10 Mabi Coins
• Play 200 Rock Paper Scissors matches:
  • Title: Rock Paper Scissors Expert
  • 10 Mabi Coins
• Play 300 Rock, Paper, Scissor matches:
  • Title: Rock Paper Scissors Master
  • 15 Mabi Coins

They are absolutely not alike, and thus not plagiarized, since it is understood that aside from the rewording, the information already belongs to Nexon. If you wish to see an example of where there should possibly be a reference tag for lack of rewording, take at look at MabiLand 7th Anniversary Celebration Event#Rock Paper Scissors Details, a place where I did indeed neglect to properly reword text from the event announcement.