I have several friends in Alaska who on multiple occasions have encountered grizzly showing up shortly after a game kill, moose, deer, what ever. It's become such a common phenomena, that they have made it a regular habit to prepare for such an attack. They have told me of incidents while dressing an animal out and quartering to pack it out, they have had to run bear off with warning shots only to have them return 10 or 15 minutes later, and then again following that. They are persistent. Some have said that while packing game out that bears have been spotted following them, apparently waiting for an opportunity to make their move. They are highly intelligent, and whether or not they associate the blast of a firearm with a waiting meal, who knows? But what we do know for certain, is that they have a nose for blood, which is far more likely the trigger that brings them in searching for an easy meal.
Bear spray is ok as a last resort, but it's best to have some lethal means at the ready, especially when dealing with grizzly. My buddy and I tried pepper spray, it almost seemed to aggravate and change it's mood. I have on multiple occasions had run in with bears, and although they have been black bear, they have been no less persistent, and just as potentially deadly as a grizzly.
I ran one off 3 times in one morning while at camp in S.E. Arizona some years back. It returned again for a similar game of cat and mouse that evening, we moved camp that night. And I have had my camp raided numerous times while in the tent. Bears are unpredictable, and to trust them, is as if to trust a rattle snake. I bumped into a guide and his client back in the 90's, in which the client had his buttocks ripped clean off by a black bear he thought was dead. I assisted in doing what I could to help while medical personnel was in route. The fellow made it, but one mistake nearly cost him his life.
I prefer my coffee hot, with cream and sugar, but it's always so much better while sitting around a camp fire with a loaded big bore handgun on my hip.
GS