We have explored adding the ability to set event detectors to not raise the event more than once in some amount of time, but that feature was not merged in at the time so hasn't become part of Mango yet.
I think what you're requesting would be something like that, but for data source events, which is a good idea if it is a good idea to do it for event detectors.
it doesn't sound to me like that'd solve how his users are going to identify points they want to control and control them easily. That's going to be an issue only his implementation of a dashboard / Mango could completely solve.
Agreed, but as he was only able to give an example without greater in depth information on the desired outcome, only wishing to be able to add multiple points to a context. I'd give him what I knew was freely available. I do not believe he wants to go into the grit of a custom dashboard page at this time. However, if that changes I'll be more than happy to assist.