I must have tripped my Knox counter when I installed the official Samsung 4.3 update via Odin (as the mobile Odin method made a mess of things concerning the kernel which resulted in no WiFi). I just couldn't get Kies to play ball for me so that's why I resorted to Odin. In all fairness though, I've had the phone now for just on 14 months into my 24 month warranty. Given how reliable it has been, I don't have any warranty concerns and if anything should happen as far as common problems are concerned (with the USB port, for example), then I can easily fix that myself anyway.
As a consequence, it was enough to spur me on to install the Ditto Note 3 ROM instead.