One difference is that anyone calling YOU from SXM would need to make an international call. AND it wouldn't work if you don't have wifi, so if you're out in your car, and you have an issue, you would have to make an international call to call anyone for help.

Are you going to take Sharon's phone with you to see if it works? If so, please post here after you check it.

So far, I haven't heard back from Sharon..