Under Preferences, Network on the Treo and then Options, Preferences once you get to the Network page, it provides the ability to check and "Connect to the data network whenever wireless mode is powered on."

The information for this option indicates that if the box is checked, the communicator will register with the data network as soon as the wireless device is powered on. Has anyone used this option? Any drawbacks? Any potential additional MB charges once SPCS starts charging?