That is a very good point to remind us all about. There are some intriguing anglees to that problem/questions that raises, too.

Looking at it from a mechanical point of view:
Since we are always scanning for information that will solve our relevant problems, if the teacher packages the information in packets that are too spcific or narrow, it could be perfectly correct but totally ignored. If, on the contrary, the information/solution/resource is move vague so bits will appeal to a potentially larger range of people. This the lesson from fuzzy logic in information sceince. Erickson's use of indirection take advantage of this principle. Then, as individuals orient toward any aspect of what was offered, he would notice and calibrate what worked, and do more of that.

From a more spiritual point of view:
Once a person is trained to do the above as a manner of interacting, he or she should 'let go' and not attempt to force anything with conscious intention. There seems to be a balance between deliberate intentional shaping of information/intervention/probing on the one hand, and doing nothing on the other hand. That is, allowing things to happen, allowing the student/patient/child to influence the teacher/therapist/parent.

With that 'letting go' being done both by the teacher and the student, and awareness continues, a creative magic happens. Observing the process people have come to say "the teaching appears when the student is ready".

Or something like that.