At secondary school the uniform should be shirt and tie, IMHO and changes should take place at the end of the year (also IMHO). I'm sure they have a good reason for doing it - change in logo maybe?
Edit: I thought SATA replaced the need for jumpers.
Edit2: IBtL.
Are the jumpers set to short or open? You really only should touch them when you need to reset BIOS due to a bad overclock.
The jumper and polo shirt uniform is the new uniform getting rid of the ties and Blazers