This.
Will also say that if either of your students go into a field in which un/low paid internships are essential (IR / poltics / policy are notorious for this), be prepared to figure out some trade offs. In order to get (what will be poorly paid) jobs after graduation, those internships are essential. If the student has to get a summer job to earn enough to pay for living expenses during term an internship becomes difficult to impossible. Have principles, not rigid rules, and apply them thoughtfully to the given situation. Your goal is for them to learn financial responsibility- engaging them in conversations about what/why/how different trade-offs can work (or not!) is at least as useful as pronouncing a set of rules.