Last school year our district had a rash of "threats" at our both our middle schools and at the high school. The school board and administration took a very firm stance that this behavior WILL NOT be tolerated and they quickly expelled any students involved in the activities. They also ceased giving days off due to the threats since that seemed to be the whole idea behind making them. Security was upped and restrictions on backpacks, purses and clothing were made. Your district needs to take a hard line on this-if someone is caught making threats, they are out the door, no excuses.
As for prevention: our schools increased teacher presence in the hallways(especially around the bathrooms) during all passing times. NO ONE left class without a pass and they were expected to go directly to their destination-no deviation. Our parent group also helped to purchase additional security cameras that were installed in hallways near the bathrooms so staff could monitor who went in and out of the restrooms and timeframe spent in the restrooms. The threats finally stopped.
Also, many of the students got sick of the interruptions to their day and no longer were amused by these antics. That probably had the biggest influence on stopping the behavior-if no one thinks it's cool or funny, the kids stop doing it.
All the school would discover is how often a particular child had to "go". Unless the bathrooms are inspected from top to bottom every hour or so of every day for new messages, scanned admittance to the bathrooms wouldn't help identify the wall-writing culprit whatsoever. It wouldn't even narrow down the possible suspects all that well (especially since there is no way the school could keep up bathroom inspections on the hour for the long-term). It would be a waste of a lot of money that could go towards other purposes.
Our middle school has already had 2 "threats" this year. Twice messages have been found on bathroom walls threatening acts of violence on specific dates....Thank goodness these have turned out to be pranks...but not harmless..... it does have an effect on students not only taking away from class time ( back pack & locker searches every day now until Thanksgiving break) it is also scary. Our school already uses ID's to check in library books, pirchse items from school store and cafeteria......some parents have asked if these same ID's couldn't be used to open doors (scan at bathroom entrance).
Is this even a possibilty? What are your opinions? Is this something a PTO should consider purchasing??? any response is appreciated.