I believe so.

Sometimes, even by falling off of high things.

I contend that this particular individual died because he was drunk and foolish, the fact that he was 'planking' whilst drunk and foolish may have contributed to it, but was not the only cause. Accidents tend to happen when people are drunk, as it affects things like judgement and balance, both of which are vitally important to not falling off the aforementioned high things.

The separate case of the guy being arrested because of 'planking' on a police car; as mentioned by another poster above, the police are quite likely to arrest you if you site/lie/jump/plank on top of a police car, what with there being a law against it.

As to where Facebook comes in all this? The easy answer: it doesn't. The supposed link between the 'craze' on FB, and an unfortunate drunken 20 year old losing his life is so tenuous as to be non-existent.