Any risks the system finds can be overridden very easily. If you go to the particular asset, then drilldown to the Risk Register, you'll see a list of the risks it has found. You can then click on one of those risks and click "Ignore / Modify".
In this form you can specify whether to ignore the risk or just modify its impact:
Once this is changed, all risks will be recalculated again to omit that and any associated risks.
Next Topic: Contingency Planning