If he provides the two-key option, then he is definitely trustable...
I'm probably saying something that everyone here already knows, but:
The two-key coin requires both the private key on the hologram and your secret key to redeem it. This means that
1. Since the address of the coin is easily gotten from your two public keys, you can verify casascius sent coins there.
2. He has no incentive at all to put an incorrect private key onto the coin.
3. Thus, you and only you can redeem the coin.
The point is that he holds all the information to extract the underlying BTC
at any point, not that it's an incorrect private key. I.e. there certainly are BTC on the coin. A week later, a month, etc, there aren't. Random sample, draw from an address that's on an old coin, easy peasy.
Again, I'm not saying he's doing this. Only that this particular business model is
the perfect scam as soon as he gets greedy enough. Maybe he isn't this way, but given the general history of "bitcoin entrepreneurs", I don't know why you'd take the risk.
I got the sarcasm of the statement but I was wondering why not put a valid BTC address there just in case someone agreeded with the statement.
Because it gives me an opportunity every time to say this: you are a sad, sad group of people begging for change on the internet corner, and it sickens me to the point where I wouldn't put a public BTC address up if you paid me.