Mike Caldwell, 2901 Little Cottonwood Road, Sandy, Utah 84092,
who appears to be a trusted member of the Bitcoin community. They provide a digitally signed list of Bitcoin addresses and claim that this makes Mike legally accountable. (I'm not sure how the GPG key used can be connected to a real person.)
The only form of payment, they accept directly is Bitcoin.
Such a service allows for two types of fraud:
At some point in time, they stop sending physical coins in exchange for BTC received and disappear. This is a very common risk when making payments in advance and it is particularly obvious if the form of payment is designed not to allow chargebacks. The risk here is not different from shopping at many other businesses online. However, the relatively simple website and the connection with Bitcoin, is likely to raise alarms with customers.
Although they claim otherwise, they could easily keep a copy of the private keys. This would allow spending the balance on all coins that have not been spent yet at some point in the future.
What should the Bitcoin community expect Casascius to do to render the scheme trustworthy?