Phones were not permitted in school during school time but I went to high school in the late 90's (yes, I'm old). At that time, everyone didn't have cell phones stuck to their ears like they do now.
I think the reason there is an uproar over kids having cell phones at school is because parents want to be able to get ahold of their kid(s) anything they want. Before, you'd have to call the front office and ask the staff upfront if you can talk to your kid. Well, if there's something going on at the school and the parents want to talk to their kid to see if they're okay, the parents want to be able to talk to their kids right then and there instead of having to wait for someone to go get them. In some scenarios, it may not be possible because too many parents are calling the front office to talk to their kid. So the parents are always going to grip and throw a fit that they want to be able to get ahold of their kid if there's ever a problem while they are at school.