Not that people are actually allowed to do that for a whole host of reasons, however there are still a lot of people that think its a good idea, citing the fact that they managed to get through school without using a cell phone.
However, most of them miss the point. The fact is that our culture is changing and mobile communication devices are becoming an extension of our daily lives. Blocking those devices from working is not solving any problem.
What the schools should be doing is teaching the kids how to get on in the world they live in, which includes proper etiquette on the use of mobile technology.
Think about it, its no different than talking in class when you are supposed to be listening. There are protocols that the teachers go through, there are reasonable rules for the students and there are consequences for ignoring them... so why would a cell phone be any different?
It seems to me that there are a lot of people who are unable to adjust to rapidly changing culture, as there has always been.
Maybe the educators need to be educated.