mw13, Kids are naturally versatile, intuitive, astute, and clever. They WILL find ways around “blocks”. They can even find ways around their activity appearing on the monthly detail section. Trust me, it can be done, it has been done, and it will be done.
And this is aside from the dangers involved from unfettered VOICE ONLY access. Surely you are not oblivious that unfettered access to RECEIVE (which are not detailed on the bill where it originated from) voice calls can be catastrophic?
You are playing with fire. People HAVE gotten burnt, and worse…