As an a cappella singer, I like it when the rehearsal leader follows this principle. As a teacher and choir leader, I notice that it gives good musical results.
Example: first sing a song, or do a few exercises. Then reflect on what you just did together.
If you do it the other way around, for example that the choir leader begins with a detailed instruction, gives an in-depth analys, or starts a group discussion – then the musical experiences of the singers may have to be fit into a theoretical structure, while they are singing. As if you would try to squeeze your feet into a pair of shoes that are too small for you.
Better to give the shoes some time to adapt to the shape of your feet. Better to first give the singers a chance to get familiar with the actual music.
When singers are given chances to experience the music, without first being given a detailed instruction or elaborate analysis from the choir leader, then this often leads to questions, sooner or later. When questions emerge spontaneously from singers, then it may be time to provide perspectives on the purpose with a specific exercise.
TIP for leaders: when you facilitate a rehearsal like this, then be prepared to have a response to questions like: "why are we doing this?" after having done an exercise.
QUESTION for singers and choir leaders: if it turns out that a map (or expectation) of yours does not fully correspond to reality, would you then change something in your map – or would you try to change the reality?