Helping schools in pressurised environments (Safeguarding)

This morning a school rang to ask about our registration app.
This is an app that some sixth forms use to check-in students who perhaps have more freedom around school than students in younger year groups. Our app allows a sixth former to check in provided they can be located within defined geographical areas of the school using  GPS location through a branded school app that we provide.. When the student checks in they can select their activity from an appropriate list set by the school. This "registration" can then be written back to the MIS.
Parmiters school in Hertfordshire @Parmitersschool was the first school to use this functionality, but others have followed and it is now being used by one of the big Ivy League Universities in America to monitor student engagement with different professors.
However the phone call this morning wasn't really about an app. The school was a special school with students encompassing a wide range of ages and abilities. The deputy head teacher's vision was that after first registration, when a child is marked as present, but then doesn't arrive at one of his subsequent lessons that day, the absence is flagged up to the office and the student can be located. With their students, there were a lot of safeguarding issues that needed to be covered.
I have subsequently found out that this is an issue with all secondary schools, where students are expected to navigate around schools without being herded by teachers. In actual effect, we asked why their MIS supplier wasn't providing this, but apparently the supplier suggested that the school manually cross check against each student timetable.
We have suggested a web site that could be developed relatively cheaply, into which the school registers each child at the start of the day, this is then written back to the MIS. Then at each lesson, all the student's timetables having beem imported to the website from the MIS, any students who were present at initial registration but who are missing at this lesson are flagged up to a safeguarding member of the school by an email , or if the school wishes by a push notificaiton to a member of staff....
It all sounds very obvious and it is a real surprise that their MIS supplier is not offering to develop this for them within thieir existing technology.
If you are a Head teacher and have read this and would like to investigate developing something unique for your school, contact Peter@ideafarm.co.uk or ring me for a no obligation discussion on 01625 572922