No and no. Only people who've set up accounts will show up, so if they never touch their earpiece they won't be on the list.

[It's opt-in, basically. Chances are there are a few people around who don't want anything to do with the network, or don't understand the technology and haven't asked anyone for help.]

You can call him, but he can choose not to answer. We've all got digital inboxes though, so if he doesn't you can still leave him a message.