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.
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.
This quite sets them apart from "regular old 1 BTC casascious" coins, which can actually be given to someone.
This thing is bound to an address owner. I see, much better for storing wealth, casascius can't steel the bitcoins, neither can anybody else getting his hands on the physical product.
Pretty save against theft, I'd say. Cool, that's what was missing so far.
Thanks for mentioning this, because I really didn't catch it before
