Earlier quoted context omitted.
No, at some point between $0 and $400,000,000[1], negligence is no longer an acceptable excuse. [1] The current market value of the claimed 700k BTC loss in USD.
Oh please. Saying that bitcoins are worth $400MM is like saying that a collection of "limited edition" Beanie Babies is worth $400MM.
You can ascertain the value of 1 BTC in your favored currency rather easily given a choice of marketplaces. Less so with 100, or 10000+. Most market-places couldn't handle the volume without a substantial shift in price before your 400mm mark was hit for say, USD.
That said BTC seems to want to reach the type of ubiquity that allowed USD to be a universal currency of sorts during it's heyday. With means to convert in and out being varied from the strictly regulated to the strictly unregulated.
Now let's see how long the blockchain can live.