Seems like a golden opportunity to say "Sir, this person may be dangerous and may still be in the area, it would really be better if you would just return to your vehicle and wait for the officer there." making a recommendation like that and conveying concern like that requires no authority.
So perhaps, just maybe, the dispatcher didn't see the act of merely being outside of your car, in your own neighborhood, to be equivalent to hopping out of the Land Rover on a safari.
Maybe hindsight is the only reason anyone thinks George's actions are reckless and irresponsible. Oh and by the way I wasn't saying the dispatcher was giving approval of anything, just that I think it's noteworthy that he didn't devote more than, at best, those initial few words to the supposed perils of getting out of your car.
Perhaps the problem was that George wasn't cynical or suspicious ENOUGH of Trayvon. Since apparently he didn't consider that Trayvon might come and do violence on him.