If you know your source code, then whether you actually smoke cannot provide additional Bayesian information on whether you are likely to get lung cancer. Your decision is a logical consequence of your source code, and Bayesianism assumes logical omniscience. Humans in general don't know their source code, but if Susan is using a formal decision theory to make this decision (which should be assumed since we're asking what decision theory Susan should use), then she knows her source code for the purpose of making this decision.