When to register events

Hi Forms WG, and in particular XML Events implementors,

For XML Events 2 we have had a request that we be more specific about when  
listeners get registered.

We would like your advice:

1. What should the spec say about when listeners get initially registered?

2. Should the listeners be live? In other words, if the DOM of the markup  
gets changed, chould the listeners react?

Thanks for any advice you can give.

Steven