So what's the point of the prompt? Right now, it's just annoying when you're travelling through a forest, without helping you in the least, anytime. Is there any reason for the feature?
The point is to make you realize the game world is not flat, to make you be mindful where you go, for the purpose of immersing you deeper in the game and perceive fences and bushes as obstacles they are.
When you try to move over such obstacle you already make half the effort, the prompt is about giving you a choice to abort the action, hence time penalty. The point is to play more carefully, watch where you go so you don't get that prompt unless you actually wanted to climb over such obstacle in the first place.
