No they were not. People who went to third party sites and bought DB only items were banned. From expansion code keys to krono, didn't matter, they got banned. Many were unbanned with just a warning. The big lie going around is that innocent players bought krono in game for plat and were banned. Never ever happened.
Another toon in game. trade/parcel... Krono are really secure for what they are and DB can and does track each and every one. They know who bought them, how they bought them and where they have been. If your account is in good standing and played like pretty much every other account in your "free time" zone, there is no way you'll get banned for innocently buying or selling a krono in game. It just isn't going to happen and it's ignorant fear mongering to claim innocent players are getting banned for trading krono in game. We are talking getting banned here, not, a 24 hour or week long suspension for having "innocently" gotten involved with the wrong people.
No ones getting banned because they bought/traded for a krono in game. If person A does a chargeback on the krono person A gets banned and they take the krono ya sucks but they will not ban Person B aslong as Person B has no connection to person A (ip/email etc).
If you do that and they are able to trace the trail to any of your other accounts I suspect they get banned too.
Always wonder if krono speculators like to put out these rumors about people getting banned for buying krono in game in hopes it will drop the prices so they can scoop more up. If they were banning people for buying krono in game for plat because there was an issue with the krono there would be hundreds of players getting banned. Now if an account received krono from some sort of scam and the account could be traced back to the scammer then yeah I can see it getting banned.