I am actually thinking about the possiblity that if you have 4 crew...1 BA operator...And the next MFS or CFS backup is 5-10mins behind you. That it may do good just sending that crew forward to that job, to do what ever they can do. Time Critical Incidents Especially.
Again,we are talking MFS area only, they don't include you as part of the response, your a bonus, if you don't respond it doesn't actually mean a great deal, as they are still sending their minimum response if you turn out or not. You will always notice that most times for a 1st alarm domestic you will have 2 MFS pumps and 1 CFS. Same with an RCR, eg : if the crash is in MFS area that the green book says should be Glynde and Athelstone, 204 or 329 will always be added as CFS don't count, they are to unreliable.
So therefor if you respond, all well and good, but do it as they ask, if you don't ring them and default, but it won't matter unless they are extremely short of trucks, but in that case you will most likely be sent COQ anyway.