Tricky one this. Insurance is all about risk ultimately, that's why occupation is considered, as certain occupations are statistically more risky. Is your second job actually a job or more of a hobby (like many of us here, I suspect)? If so, I would not consider it as needing disclosed as a second form of employment.
Insurance is in most cases based on 'good faith'. That is, an insurer will cover you if you have answered everything honestly and truthfully to the best of your knowledge. We can all do things to reduce our premiums to the lowest they possibly can be but ultimately could be caught out in the event of a claim, so false economy.