Lanefan
Victoria Rules
Two issues here:A group of 4 level 10 characters at full strength going in a cave to rest for the night with a single black bear guarding it's den.
The potential ethical argument about kicking a bear out of its den to sleep or whatever might make for an interesting situation for the players but the "roll initiative" challenge of actually defeating the bear is non-existent. In this scenario I would not run a combat if the players wanted the bear dead or driven out, it would just be narrated.
Same situation for that same party being attacked by 8 low level bandits with daggers and leather armor.
One, if you're using a system that has fumbles etc. that can cause weapons, shields, etc. to possibly break then every combat of any kind has potential long-term consequences.
Two, by going to straight narration you're not allowing for the one-in-a-thousand chance that the supposedly-inferior opponent gets hella lucky and badly hurts or kills a PC or two, or even wins outright.