I think this is likely a good concept for schools, but I want to see the data and not opinions. Lack of evidence based policy is what got us here, we should at some point start using evidence based policy to get us out of it.

There are many sources for data on before and after school cell phone bans. Oregon is far from the first to implement this. 35 US states have some form of school cell phone ban, and I believe the UK is doing a nation-wide ban. There is a good amount of supporting data measuring results on this topic.