After they told me that there is an order from Samsung to reject warranty when one of the bits is triggered (knox or flash counter), I asked for a written confirmation on that, and would like to get my Note back. They said they have no idea when I get it back. They even told me it was sent to Korea!!! :laugh:
Anyhow, in Germany we have a warranty by law against the seller of the product, so when I get it back unrepaired, I will check with the phone-dealer, and they have to repair or replace it since there is an EC-regulation about this.
update March 25th, 2014 : Today they called me and told me it will be repaired under warranty for free, (but again referred to the warranty conditions that say that any manipulation on the software would void the warranty)! I do not care about that, result is: My phone should be back within the next two days. So finally it was a good decision to root and not beeing too much impressed by Knox and these bluffs.
Update 27.03.2014: I've got my Note 3 back, repaired under warranty. Although they pointed out that a rooted and knox-tripped device is no longer covered by warranty, they made it.
So, don't be too afraid to mess with Knox!