I agree with Linklater that the warmup is an underutilized resource in instrumental music education. In most situations I have been in, warmups were just something quick to get everyone playing so the group could get to the real stuff: rehearsing pieces.
I can see how this is a temptation. We often program ambitious concerts and pride ourselves on polished performances. However, the warmup allows a chance to focus on some generalized skills that can really help students develop in a way that pieces do not always provide. I think this is especially true in the context of intonation.
Most students can generally tell when they play the wrong notes or rhythms, provided they know how the piece goes. However, learning to tell if one is in tune takes more focused listening. Many times, in the course of a piece, I have seen a conductor do the "point at the ear" move or say "flutes watch the pitch, you are going flat" or something to that effect. Then, upon the second playing of the passage, it is just as out of tune as it was the first time. This is because the conductor had not spent the time developing listening for intonation in the group.
Linklater's ideas for intonation are all very good. Students have to first learn what in tune and out of tune sound like, most easily done on like instruments, and learn to listen for the beats in the sound waves. This needs time and models. Without it, even if students know how to adjust the pitch of their own instrument, you essentially have the musical equivalent of a bunch of blindfolded people trying to play darts. And who hasn't seen the concert in which every ten seconds some flutist decides to adjust the headjoint. In my experience, this kind of behavior is a telltale sign of shooting the dark when it comes to intonation.
The other issue with the warmup is to make sure the students are invested. While some routine is desirable, if the warmup is exactly the same every day, students will check out fast. Similarly, if the warmup isn't understood or treated as important, students will perform it on auto-pilot. Thus, it is important to vary the warmup from day to day and to make sure that it is clear to students what the goals and purposes of the warmup are. This will facilitate attention and focus and allow the students to best benefit from a well planned warmup.
