In this paper we consider parents as unofficial evaluators of success in primary bilingual programmes that are not subject to any standardised bilingual outcomes. Small-scale, opt-in programmes that are reliant on parental buy-in are increasing in Australia. Given the importance of parental choice on the sustainability of these programmes, we seek to understand parents' evaluation of success in their implementation. We apply Mehisto's ([2015]. "Forces Mechanisms and Counterweights." In "Building Bilingual Education Systems: Forces Mechanisms and Counterweights," edited by X. Mehisto, and X. Genesee, Xv-xxvii. Cambridge: Cambridge University Press.) framework of forces, mechanisms and counterweights to two Australian studies, and explore the parents' discourse around the success of four primary bilingual programmes as a counterweight to the degree of commitment at the school (force) and the perceived affordances (mechanisms). The implications of the parental evaluations of success on the implementation of the programmes are discussed.