A a single data point, I spent an hour cleaning the K worm off my laptop after a co-worker lent me his memory stick to transfer a file. Cost - An hour of pay plus the frustration of directly not getting important tasks done.
The articles seem to state specifically that the drilling in Europe caused the earthquake. Almost without a doubt that is just a conjecture. The problem in California is that if the drilling takes a year or two, there is bound to be some kind of quake, and the drilling will get the blame. On the other hand, the value of deep well geothermal is so great that it would be worth a minor quake to get it.