Flying schools generally don't take a student out into marginal weather. The flight would be cut short, the operator would not be paid for a completed lesson, and the paid-per-hour instructor would not take much home that week.
Hopeless. I used to try to take students on nav trips where they would HAVE to make a diversion around Cadbury clouds, but the boss didn't like "DNCO" (Duty Not Carried Out) flights. So, Bloggs only ever flew on CAVOK days and the decision-making process wasn't well developed.