I remember an old friend of mine, obsessed with high notes made a right plonker of himself during a solo in big band. He squeeled like a castrated pig for 3minutes and then abruptly pulled his trumpet of his face and went Grrr! It was so embarassing! Trumpet screaming like this is equivalent to what guitarists refer to as fret wanking. All about the "show" and little about the music. A great example of this type of stuff in action is on a trumpet summit clip where Jon Faddis and his compadres where competing with screaming. As soon as Wynton started playing he made a statement by playing some beautiful low register phrases. Don't get me wrong, i love high note trumpet players like JFaddis etc as much as the next man and i have massive respect for their musicianship and playing, but ego fuelled high notes in my opinion can ruin a performance. For me, i can play up to a double C, but i choose not to practice up there because i haven't mastered the Walter Piston 2 1/2 octaves.