A rider needs to adapt to the conditions of the ride. Some places where I go, the cell phone will not always be reliable. There are alternatives to the cell phone and its the satellite guided systems.
On some rides, there is zero chance of getting fresh drinkable water other than what you carry. I think you know what to do here. Either carry more water or cut the ride short to fit what you can handle.
On other rides, its about the neighborhood, and the possibility of getting robbed by homeboys. Group rides will lessen that chance. A group ride is not 2 riders.
In California, Whiting Ranch, there were attacks on mountain bike riders by a mountain lion. One guy died and the lady got mauled. I can't remember when the attacks occurred. But we do know when mountain lions normally hunt for food. They're nocturnal hunters and if they didn't get fed, they become early morning hunters.