Sections 7 and 8 of this paper [1] discuss inducing memory faults and potential countermeasures. Specifically they indicate that many desktop PCs shipped without ECC hardware at the time of writing (2003). I'm not sure to what extent that's still true, but I imagine it could be a problem for the masses of cheap/old hardware in use around the world.

edit: I found some more recent numbers via [2]. Relevant quote: "Our first observation is that memory errors are not rare events. About a third of all machines in the fleet experience at least one memory error per year (see column CE Incid. %) and the average number of correctable errors per year is over 22,000. These numbers vary across platforms, with some platforms (e.g. Platform A and B) seeing nearly 50% of their machines affected by correctable errors, while in others only 12–27% are affected. The median number of errors per year for those machines that experience at least one error ranges from 25 to 611." They were using server-class machines with ECC.

[1] http://sip.cs.princeton.edu/pub/memerr.pdf

[2] http://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf