My guess is that the whistle is only useful if there are people around to hear you. I would always carry one in the UK as it is a good way of attracting attention, for example if you fell and broke your leg while fell walking. Though this is ‘annoying ‘, it is hardly life threatening if you’re wearing the right clothes, carrying your pack and told someone where you were going and what time you'd be back.
Where Mors roams, Canada, I doubt a whistle is going to make that much difference if you’re lost. A signal fire/mirror (shiny part of the cup) is much more likely to attract attention of a search plane!
Conventional wisdom would have you think that a compass is also really useful, but in reality they are pretty limited without a map. You can gauge your direction of travel by the sun, algae on rocks, tree lean towards sun, etc. In a place like Canada you can never travel in straight lines anyway as lakes and rivers end up dictating your direction. Moving any direction other than up or down river systems is pretty pointless in a survival situation anywhere on the planet. Anyway, you’re more likely to be found staying put which is one of the golden rules of survival.