There are both security concerns and safety concerns. By safety concerns, I mean that it's Vancouver and it's winter. I grew up on the north shore, and the Sea-to-Sky Highway seems to close down on a fairly frequent basis.
From a security perspective, I suppose the worst thing we could imagine would be the same types of things that we've just seen in Mumbai. There is, to my knowledge, no indication of a specific threat vector that would be to that extent, but we will ensure that what we have is a scalable response capability in place to support law enforcement.
But I suppose the level of concern from security is really with the movement of very substantial numbers of people. It's the activity that brings with it the level of concern. There will be hundreds of thousands of visitors, the vast majority of whom will be there to enjoy the games. I presume there will be some who will also have other interests.
The harm that could be done as a result of a wilful attempt to do harm is the reason why the Canadian Forces are being asked to bring our skill sets to bear in support of police forces. The wilful harm vector is the greatest concern we have. It also potentially could be the least likely to occur, but the consequences are the most catastrophic, which is always the difficulty.
It's winter on the west coast, so I expect stuff will happen. A capacity to be able to absorb that shock will have as little effect upon the good functioning of the games as there can possibly be.