We have studied the design documentation for two industrial software modules to see if they apply ideas corresponding to contracts, as introduced by Bertrand Meyer, either in an intuitive or in a formal way. They did not, and we identified this fact to be a potential risk factor. This paper presents one of the modules studied, consisting of a sequence of switching sections. Starting from this case study, the paper also discusses how switching sections in general can be designed using contracts in order to increase the semantic integrity of the module as a whole.