At my school, I had a sort of an unspoken agreement with the admins with the school computers. Now understand that this school was strict with computers. You had to use flash sticks for school work but half the computer monitors would go bizurk if they saw a usb stick in their computers. Pentium 3 btw. Anyway I got sick of the 70mb internet cap every day so I started to find holes in their network. All the computers were esentialy terminals, Everything was restricted to the point where you could not boot a .exe if it wasnt on a whitelist. Anyway I managed to gain a few accounts here and there, about 3 fellow student accounts, a teachers account and a good 30 unlimited accounts. They got some new Pentium dual core computers and a few i7 all in 1's. Had a bit of fun, Never did damage but then I managed to patition a pc with a linux and a windows patition, all locked of cause. But things started to get a little hairy. Student files free to access, Resaults, Teacher emails. The works so just 2 weeks left of the year, I decided to reveal all the holes in their system, tought the system admin how to block all the huge holes and such. Things seemed to be ok. I ended up just using my s3 as an access point for my laptop and didnt have any problem. a huge number of threats as it turns out I wasnt the only one with the unlimited accounts but I didnt care. But I learnt something. Even if you do it just for fun, non destructive and reveal everything, they can and will expell/refuse entry the following year.
If you want more internet, or just want to mess about on a computer, Just bring a bloody laptop instead. If you must. Dont fuck with their system, Just do what you need to get through school. Its only 6 or so hours of your life a day for 12-13 years. Once your out, it dosent matter anything you did there aslong as you didnt get kicked out before you complete schooling like I did.