If it's critical not to have problems if/when Amazon goes down, you have to plan for that ahead of time, just the same as anything else. It's not like throwing the "cloud" label on something makes it invincible.
As computers become increasingly integral to the daily operations of a business, the business guys are not going to have any choice but to learn some basics. We're really already at this point, but maybe after enough failures similar to those witnessed this weekend it will finally sink in.
I am amazed how many people want to blindly follow the buzzword bandwagon without obtaining even a vague notion of the technical implications first. The fact that Amazon would be controlling Amazon EC2 and that if a failure occurs at Amazon, their EC2 product may be affected, is the most blatant thing about using "Amazon EC2" or any other external service provider.