Final answer:
The therapeutic recreation ethical principle being violated is Veracity.
Step-by-step explanation:
The therapeutic recreation ethical principle that is being violated when the CTRS fails to discuss the results of an assessment and related plan for intervention with the client is Veracity. Veracity refers to the principle of truthfulness and honesty in delivering information to clients. By not discussing the assessment results and intervention plan, the CTRS is not being transparent with the client, which violates the principle of veracity.