One thing I struggled with while learning about Cairngorm is the Cairngorm Event model. In short, Cairngorm Events are quite different from standard Flex Events in the way they are handled.
This may be obvious to seasoned users of Cairngorm, but this took me a while to wrap my head around. Cairngorm Events map to Commands via a Cairngorm Controller. They are (as I understand them) meant to update the ModelLocator and get data from the server (via Delegates and Responders). They don't "bubble" up the Flex container hierarchy, and they don't get announced to the rest of the Flex application.
My first instinct was to try and decouple my Views from Cairngorm by having them only announce Flex events. These events would bubble up the container hierarchy and be handled at the top level of the application. From there, corresponding Cairngorm Events would be dispatched. This way, I could still have non-Cairngrom event listeners respond to the bubbling events, and my Views would be decoupled from the Cairngorm framework, which sounded like a good idea.
However, with more experimentation and thought, I've realized this approach adds complexity and doesn't offer much in the way of benefits. It requires a separate layer of event mappings so that the Flex events can be translated into Cairngorm events. And in most cases, your Views are tied to Cairngorm anyway. For example, a Shopping Cart panel is directly tied to the ModelLocator to keep track of what is in the cart. You can't easily reuse this Cart component in a non-Cairngorm app without changing it. The same thing probably applies to most of the Views. So in retrospect, in most cases I believe it is fine for your Views to just go ahead and dispatch Cairngorm events and avoid all the overhead of trying to make them framework independent.
Now, I can see that for certain kinds of components, this would not apply. If you truly have a reusable component, say a custom Select Box for picking States or something, this would benefit from being totally decoupled from Cairngorm. You can have it dispatch a custom Flex event that the parent container would then handle by dispatching a Cairngorm Event. So it appears that one must consider the purpose of the View component in question and decide whether it is application-specific or application-independent. The answer would seem to dictate whether it is appropriate to announce Cairngrom Events vs. Flex Events.
I'm interested to hear from anyone more deeply familiar with Flex and Cairngorm. Is my thinking on the right track on this? Please fire away in the comments and let me know your thoughts. Thanks!