ARIA best practice doc: new dimension to role=alert

In section "5.3. Choosing Between Special Case Live Regions", the alert role  is assigned an added meaning: "one-time notification which shows for a period of time and goes away".  ... 'goes away' appears to convey 'go away automatically ... without user action' i.e. say after 10 seconds or 30 seconds or the like.  

I do not see anything  to this effect being suggested in the normative doc that explains role=alert.
I hope this is not how 'time sensitive' is being interpreted by the authoring practice doc?

Sailesh Panchang

Received on Friday, 13 December 2013 20:51:15 UTC