"Saying something meaningful enough to get someone jailed for possessing a drive with the string on it (the criteria for this to be actually harmful to bitcoin) is nearly impossible in 20 bytes in most parts of the developed world."
In a sensible legal regime, sure. In a legal regime looking for an excuse to shut down BitCoin? Easily done. Technically the AACS key is still illegal. I think the latter rather than the former is more accurately the threat.
But then, if a legal regime is looking to shut down BitCoin they already have plenty of avenues. It already looks an awful lot like money laundering, for instance. So this line of thought is garbage... but only because there's no way any legal system would have to stretch this far to attack BitCoin, because they've got a wide variety of far more plausible attacks. It's not exactly the BitCoin-friendly line of argument you might be hoping for.
