If one destroys a building and doesn't have points to "make up" for it they will have negative points. Same can happen for influence events. Destroying buildings take away event points upgrading adds to event points.
yep its not uncommon if players destroy building, always destroy buildings when no influ events are running and wait for cvc or influ events before you rebuild this is important if your switching the type of hyper farming you are doing.
I am sure it has been mentioned before, but if you could build, demolish, and rebuild without the - points, you would be able to make points during the competition, limited only by time and available resources.