I don't know if they realized the danger they were putting themselves in or not. I do know that from chatting with some people that there are many people out there who would consider themselves relatively avy savvy that don't understand that you can trigger an avalanche without being on the slope itself. That it's very possible to trigger one from below without even being on the slope. This sounds like what very well could've happened in this place.
I had no clue this was possible before reading Staying Alive in Avalanche Terrain. I know just enough about avalanche awareness to get myself in trouble in complicated terrain, but at least I know that.