Assessing creative work is often challenging, even more so in culturally diverse learning environments, in which students and educators may not hold the same musical values. An instructor aiming to teach proficiency within a specific style may unintentionally give feedback that devalues a student’s personal creative expressions, which in many cases reflect diverse musical heritages. Such devaluing feedback can inhibit individual creative development, stifle innovation, and perpetuate sociocultural power imbalances. In this chapter examples from jazz, classical, and traditional musicians in Cape Town and Helsinki illustrate how and why idiomatic boundaries are enforced, how musical value judgments can perpetuate social inequalities, and how negative feedback can inhibit individual creative development. The chapter emphasizes the personal, social, and cultural importance of embracing musical diversity and the value of permitting and supporting developing musicians to go beyond idiomatic conventions in their creative work. Strategies are discussed for how music educators might better support individual creative development and social justice.