With the current level of liquidity in the bitcoin economy using it for large  (>10000 USD) money transfers would probably cause too much variation in exchange rates.

It really depends on the person you are talking to how much you want to play up the anonymous aspect.  There are even plenty of people that operate within the law that might appreciate it.  Examples would be medical marijuana in the US, and oddly enough no payment processor will touch tobacco or tobacco paraphernalia anymore either, since they consider it "High risk".  Not sure what that means, presumably they are worried that merchants don't have their taxes and licenses in order and they will end up eating the costs.

If I had an anonymous prepaid card with only a couple dollars on it lying around I might, but I don't.  If anyone else does that would be the obvious way to protect your credit card details.

Here I was thinking v for vendetta masks and ddos attacks against paypal.  Anonymous is in the news pretty often of late.

I've actually thought about doing just that.   Perhaps just buy them in cash at walmart and sell them online for bitcoins.  There are a couple problems: I wouldn't be able to handle much volume on account of not having much cash to throw at it and  what about mailing the things?  That kind of kills the anonymity since you need a shipping address.  Honestly it might be just as anonymous to just buy the cards and phones in cash at a store you don't usually go.