This article investigates whether lexical frequency drives stress assignment in Greek, a morphology-dependent stress system. We examine the stress distributions of trisyllabic nouns from seven inflection classes across three lexical databases (GreekLex 2, the HNC Golden Corpus, and HelexKids 2.0) and compare them with the stress patterns produced by adults and elementary school children (Grades 3 and 6) in a pseudo-noun elicitation task. Using hypothesis testing for proportions, frequentist and Bayesian generalized linear mixed-effects models, Bayes Factor analyses, and Monte Carlo simulations, we show that speakers' stress choices do not replicate lexical frequency distributions. Adults show systematic inflection-class conditioning: their stress patterns broadly follow the lexicon's dominant stress pattern per inflection class but depart from its distributional frequencies. Children exhibit a strong, frequency-insensitive preference for penultimate stress that persists across inflection classes, with only traces of suffix-specific stress preferences emerging in Grade 6. We argue that lexical frequency operates within grammatically imposed boundaries: the phonological default and inflection-class conditioning together determine the extent to which distributional patterns in the lexicon shape stress assignment.