If the event had been held at the CNE grounds, we would have had to secure both the CNE grounds and also the hotel area in downtown Toronto, since that would have been the only place people could have stayed, and there were relatively large delegations. And likely enough, in terms of trying to control the specific area of a number of hotels, it would have looked pretty much the same whether or not the meeting was held in the MTCC or in the CNE grounds.
But if it had been held in the CNE grounds, we would have had the added cost, both human and monetary, of securing the CNE grounds as well as securing the various routes to and from the CNE grounds, and that would have been a much more complicated security operation.