I have a K3 and I've had problems with it crashing lately, but I'm using an M-Edge sleeve to store it. No metal hinges involved, though there is a magnetic closure...
I also take the K3 into the tub from time to time, so I put it in a gallon-sized ziploc bag (just like I did with my K2). Sometimes the bag generates a little static electricity during the cold months, so I'm wondering if that's my issue
Never had a problem with the K2 though. K3 seems to be a particularly fragile beast.