Ignoring the capabilities kids have by denying them lessons on technology could be a bit detrimental to their potential imo. There's a middle ground that I offered in a response below

Teaching a kid there is a time and place to use their devices is educational. Confiscating personal property to limit access is just creating problems.

Also, who is paying for the $2000 smart phone that got cracked/lost/stolen while confiscated?

As I said in a comment above, good luck not getting sued by the parents during a school shooting / emergency and their kid cannot contact them.