The answer depends very much on the area where this is being done. Here in California we have the Owens River Gorge, a large well developed sport climbing area where climbers, other users like fishermen, and the managers have a good relationship. Climbers have built some crude bridges and ramparts to facilitate getting around, and toilets were put in through a joint effort. So far the ORG is a success story.
The kind of freelance trail work you show in your picture would be quite frowned upon in Joshua Tree, Yopemite, or many non National Park wilderness areas.
Given the current climate between climbers and land managers (deteriorating) I would be proactive and get the ok before proceeding. For example New Jack City, a local sport crag, has been developed for climbing including trails and other access features with the blessings of the local BLM because Jack Marshal took an interest in the place and worked with the BLM as climbing grew there.