In many years of hiking in Canadian National Parks I never have had a grizzly bear encounter but I do shout or sing in high risk areas like along creeks or where the bear food (plants) seems abundant and I do carry spray and a bear banger but have used neither.
If there is a sign saying you MUST hike in a group of four then you have to try to match up with someone who hikes like you and that may not always be easy. Sometimes there are sign-up boards for people to find other like-minded hikers on these mandated trails. I have a friend who was arrested and charged for hiking in a group of two where groups of four were mandated so the Parks people take it seriously.
There are not that many trails where groups of four are mandated even though groups of four may be recommended on many trails.
