If you are old enough, and still have your memory intact, you may remember a time when toilets used a lot of water. As much as five to seven gallons per flush many years ago, and that's a lot of water down the drain. By the 1990s it was decided that this was unacceptable and that we should all use more efficient toilets- and so it was decreed that all new toilets sold in the US would use no more than 1.6 gallons per flush (as opposed to the then standard 3.6 gallons). The problem was that the technology wasn't up to the task yet, so it often took two or three flushes to do the job instead of just one- so the savings were less than expected, and in the worst cases the "water conserving" toilets used more water in practical use than the old "wasteful" ones. The uproar led to a variety of oddities, from Dave Barry's popularity (OK, maybe there was more to that than toilets, but low-flow toilets are still are mentioned in his bio) to alleged cross-border runs to Canada to get "real toilets" before the laws changed up north, too. Technology has finally started to catch up with the task, and a lot of water is being saved, but redundant flushes are still often required.
Technology budgets, and especially security budgets (because many just think of security as only an expense/impediment) are under extreme pressure at this time, and the demands for cost cutting are great; the danger is in falling for false economies when trying to save money. If you can cut costs without cutting corners, that's great- this is a good time to carefully review expenses and look for potential savings, as long as you don't make unreasonable sacrifices.
Flushing twice isn't a viable option in security.