[rando444]

I regret mentioning VPN. Most people don't VPN with their phones, it's possible, but most people don't. They use their phone to access their company e-mail and sometimes other services which are open on the internet already. It's a small amount of traffic compared to the cost of trying to maintain an entire separate network just for some one-off use cases, forcing people to sign-in, register their devices, maintain the network, etc.

Of course there are special cases for tablets and such, but you'd treat those differently than someone's personal phone.

If they were given a connection "straight out to the internet" then it's even more bizarre to require strict regulations about their phones.

I see no advantages to letting people's personal phones on a corporate network.