If one implements security measures in or around technical installations in general, or large water works in particular, this may have safety consequences. Consider, for example, stricter access requirements that make it difficult for people to enter a building. These security measures will also make it more difficult to get out of the building. This can be a hindrance in the event of a fire. We did not include this aspect in our investigation into security risks of flood defenses. It is an intriguing question, which is worth investigating further.