"Jack of all trades master of none" springs to mind if people do too many sectors. You have to be careful of spreading yourself too thin which also brings recency into the equation.
I think i'm right in that in the last pay deal this wasn't involved as the union didn't want to be seen to be encouraging people to do too much.
With the predicted traffic levels of this summer I'm glad of my two sectors and am gonna keep it that way as long as I can.
Back to the original topic, I was one of the DTY/CLN bods on the night in question and was pretty frustrated at not being able to take traffic on as the LAS said I was not allowed as the airspace was CLOSED. I wasn't even allowed to delegate it to TC East or Mastricht