I have a SPOT tracker. For $150 a year plus the initial $120 or so, you can set up a personal page (EXAMPLE) and have the thing track you online. If people are worried about you, they get used to how the SPOT works. They have a newer version that's coming out. It also has an SOS button that will eventually result in a 911 call, or you can push an emergency button that results in a message to someone you set up. It's not 100% reliable, but if it can see the sky it gets tracked pretty well.

For entertainment, you can hit replay and watch me ride 750 miles HERE