In this work we explored proof schemes used by 41 middle school students when confronted with four mathematical propositions that demanded verification of accuracy of statements. The students' perception of mathematically complete vs. convincing arguments in different mathematics branches was also elicited. Lastly, we considered whether the students recognized and identified advantages associated with using justification models different from their own in order to offer a theoretical account for how individuals' proof scheme choice might be impacted by such an exposure.