I looked at those road ID's and thought they were a great idea!
Personally- I'd get the ankle one.

I usually ride with a lanyard around my neck with my lock key, and a compass/ whistle on it tucked under my jersey in my cleavage - yeah it's ample enuff!

But I think it might be a bad idea to have something like a dogtag around your neck, especially if you ride in an urban area- I understand that in in one incident in Ontario, a woman riding alone was snatched by a perv and murdered, and was strangled with the housekey she had on a string around her neck.

I know- a sobering thought, and it sucks to have to think about it- cause you can bet a guy would never really give it a second thought, just toss the thing around his neck and go....
but unfortunately, that's the world we live in.

And no- they haven't found the guy yet- he's out there, keeping women terrified when riding local trails.

Kimba