I am not sure if it was intended to be this way or not, but I think the game could have made a better provision for these things.
It is too easy to have the person taken out before you would normally find all the snow globes. There should be someone there that you would expect would be there until the end of the game. Or, let me interact with the display stand like I did with the Bobbleheads in FO3.
Well, I think it they kill Mr. House, then they should manually put them on the display case, but they wont get 2000 caps, I mean, the snowglobes are pretty much ingame with House in mind.