Just because students are out doesn't mean the school isn't occupied! I used to work as a network admin at a boarding school, and there would usually be at least one "off-site" staff member working past midnight each day (and of course, on-site staff 24/7, although thankfully most of them sleep at night), as well as staff coming in at the weekend.
Computers have become mission critical in schools now - lessons, paperwork, planning, organisation, telephones, intercoms, security cameras†, locks‡ were all computer-dependent. To date that school network is the most advanced, highest-uptime network I've ever worked on: two server rooms (network continues at almost full capacity with the loss of either) in separate locations and a backup server in a third location. Unplanned outages were basically non-existent, and the loss of any service was very rare and involved lots of people shouting at us :(
† Internal only, external were still on tape
‡ I don't mean all the doors open if the network goes down, but the electronic locks were controlled over the network