Any of this is plausible and may be required in any legislation. But when it comes to Bitcoin, it's quite easy to find a legal solution to get rid of if or pervert it:
Just add a requirement that VAT & friends can be processed in real time:
http://bitcoinmedia.com/the-brave-new-world-of-mobile-payment/
This would IMHO take care of Bitcoin, without even targeting it. It would force the payment providers to implement an RTPay gateway.