Originally Posted by Exodus
Depends on the phone. The native hotspot on Android 2.2+ has been replaced by some OEMs/Carriers by an app. This app funnels the data in a different way. For example, when using an HTC-branded device on Verizon, data is funneled through two gateways; vzw3g and dun.vzw3g. Anything funneled through the dun gateway is reported as tethered, and rooting doesn't change this. You have to manually enter the EPST settings and change the tethered data gateway, or you can simply use another tethering app.
Also, going too high on data doesn't confirm to your carrier that you're tethering. Each carrier handles it differently. I used a peak of 7GB in one month on Verizon, but a friend of mine goes over 20GB every month, and Verizon hasn't said shit to him. He's still on the grandfathered $30 unlimited plan without tethering.
So, rooting alone doesn't simply open tethering. Some ways of free tethering don't even need root, while others do, but this is independent of root access.
He has an EVO. Pretty sure if he has to apply the "fix", which is easy, it will work. If he's new to Sprint, he should go for it. If not, I would make sure to stay near the data he usually uses. They have been "cracking down". Many ROMS have the fix built in. I use a ton of data. So if I started tethering regularly now they would notice. Whether they would do anything is a different story, but they don't just allow it anymore. Some get warned or worse, some do not. Really think an EVO needs root to tether.