I remember when I was 7 starting on piano- there wasn't the slightest hint of improvisation in what I was taught, it was all rote, and I can't think of an instance (admittedly, nearly 60 years later I won't remember much clearly) I EVER heard words like "mess around", "have some fun with it", "explore everything about the instrument"...I utterly refuse to avoid this with my students, so I'll challenge them to come up with any random melodic fragment, or a chord, or a rhythm, and spend at least a minute or two exploring it.