Originally Posted by
star_world
This doesn't apply if the call goes directly to voicemail, which it would if the phone radio was turned off. There is no charge for "trying to find you" in this case.
For most networks you won't get charged even if the phone is on, it rings, and it goes to voicemail.
In theory you are correct, but if you flip the radio on and off it is not instantaneous. Many cellular companies hold your registration information cached in their system to keep you locked to their network. In 2008, I was at Gitex in Dubai and there were companies exhibiting this equipment. I got burned in Africa when I tried turning my cell phone on for only ten minutes in the morning in ten minutes in the evening to see if messages arrived.
Spend a few minutes googling on the phrase "roamer OR roaming AND capture AND revenue"
When I go down this path, historically people have argued the point with me. I'm only relating my experience.