My wife and I were just talking about the safety/crime potential aspects of this last night as we were walking around our downtown.
One one hand, you have more people walking around town
absorbed by their phone. Are they more likely to be involved in or cause an accident? Are they more likely to be victims of muggings and other crime?
On the other hand, you have more people walking around town
putting more eyes and feet out there as local citizens. Are they more likely to affect the social climate in a positive way? Are they more likely to start friendly interactions that wouldn't have triggered otherwise?
No doubt it's a mix of both, but from what I've seen so far, it's been overwhelmingly the latter. Right now the game is getting a ton of traffic and publicity, and the newness will wear off for a lot of people soon enough. I suspect that in a few months, it will probably fall into a smaller niche of rotating dedicated players, and whatever effects we're seeing will fall off with it.
Meanwhile, it's still a lot of fun finding these little pocket monsters wherever you go.