Comment More Information Please (Score 1) 818
There isn't enough information here to really jump on top of the school for giving this kid detention.
I worked as a tech in a public school district for just over 5 years, we did our best to keep the school's machines locked down tight. But there isn't a lot you can do against a student bringing FireFox in on a USB drive and surfing the net, bypassing some of our security. (OK, there is a lot you can do to stop this, but I'm not going to debate that now.)
The school may have certain rules put forth about running unauthorized software. The student was told to stop and didn't. I really don't see anything wrong with the dention.
On top of that, as some others have mentioned, we know none of the back story. Does this kid have a history of being a troublemaker, especially in terms of the computer (we routinely had "reapeat offenders", kids trying to break into the school network and getting caught.)
A little more information on the schools rules and exactly what had happened would be nice before jumping on anyone about this.