This reminds me of my Connecticut childhood. A friend had a pool which was built without permits; building it with permits would have caused the property tax assessor to notice and increase the property tax due. Every fall, after closing, we would build a wood frame inside the structure of the pool, cover the pool with sheets of plywood painted to match the brown grass, and cover the plywood with leaves, etc.
The assessor used aerial photography year-to-year comparison, done in the fall when the leaves were off the trees, to look for unpermitted construction like this pool. We hid the pool!
This system would have been a lot easier.