[DennisP]

That's a simple contract, but...

If the ICO implements that, there's no protection from someone replacing the ICO address.

If buyers use escrow contracts, they have to confirm their transactions before the ICO closes, so for typical hard-capped ICOs you don't have much time to verify things. When the crowdsale's website is displaying wrong information, there's no other source, and the sale is rapidly approaching a hard cap on contributions, there's not much you can do.

A better defense against this type of attack is to use the Ethereum Name Service, and publish the address well in advance. It would also help to use crowdsale structures that don't incentivize a mad rush, such as:

http://www.blunderingcode.com/fairtokensales/