I have to say that the odd capsize in going to happen.
I'd split mine up as follows
Pilot error - wild gybe in lots of wind when I over rotated and just blew over.....
Pilot error - too much plate down with the kite up - splash
Pilot error - I'll just keep the kite up a wee bit longer to catch that F18 / lap that 49er again etc
Other factors like people splashing in front of you and you have to take violent avoiding action.
But the ideal place for capsizing is when you are out training so you can learn the limits without loosing race places.
I would say that if you tip it in going up wind you really are not concentrating properly....