I would argue that this isn't always the case. When tasking a subordinate you should also consider where they fit in a matrix of competency and confidence. If they are competent and confident in their ability to carry out the task then what you described is fine. If they aren't competent I'd give them the task but keep a very close eye on progress and be ready to step in with feedback before things spiral out of control. If they're competent but lack confidence I'd probably have them walk through their plan with me first. This can help them feel more confident in the approach that they planned to take. If they are neither competent or confident in their ability to perform the task I'd question why they're being assigned it.