One of the posts here blames 4 line inflatables. The only thing that is wrong withe these kites over any other type is also the thing that is right with them: They can be depowered to an incredible degree. This means that you can chose to use a 4 line inflatable that is much bigger and more powerful than any other type of kite. When things go wrong, it's going to hurt more.
I have owned over 8 different 4 line inflatables over the past 4 years, and they can and have all be reliably and completely depowered with the standard safety leash that is sold with these kites. It is completely false that 4 line kites dont depower, even in strong winds.
What caused problems like this is line tangles. This can affect any type of kite.
A quick release may have helped Silke, but more importantly - riders keeping more room between each other, and kiting in safe beaches with no hard objects is the key.
We should learn from this, but also remember that many many sports can be dangerous - especially kitesurfing. It's too easy to get overconfident and forget the risks,