wrote
This raises a question I thought of recently, but had not bothered to
> ask anyone about. Suppose I start a cell call in local but move to a
> roaming tower during the call? Does the call get charged as roaming
> or not? What about the opposite situation, start of call is roaming
> but moves into home area during the call?
Won't happen. The call would be dropped. AFAIK, a change from "home" to "roam" means you are changing carriers. Calls in progress are NOT passed or handed-off from one company to another. (It appears that they usually can't even pass from one tower to another within a company.)