As always, I would assume the media only gets the story half right, at best.

The decision to stop a search is never easy, and depends on a number of factors. The chance of survival is only one of them.

If no clues have been found after 6 days of thorough searching, the question becomes what do we do now? Do we search the same area again, on the chance that we've missed something? Or do we expand the search area? If we expand the area, how far out do we go? Remember, the potential search area goes up by the square of distance from the last known position of the subjects. If you have already searched the most likely areas and found no clues, how much bigger can you hope to make the search area?

Another consideration is available resources for searching. I'm assuming most (if not all) of the ground pounders are volunteers, taking time off from work or family. After 6 days, they may well have burned through most if not all the available resources. Ask yourself how much of your time would you be willing to volunteer to search for someone you don't know?

Helicopters are very expensive search resources. And even if most of the ground pounders are volunteers, there are probably a number of RCMP paid personnel running the operation. Given the amount of complaining one hears these days from the public about the cost of SAR, after 6 days the search managers may well have felt under considerable pressure to wind down the search.