You're lucky. A more creepy way of getting enlightened is having Google Now tell you, "I see you're at work, and it's about your usual time to head home. Traffic is heavy on the usual route, though, so it might take 15 minutes longer than normal."
(This all without you ever telling which location is your work and which is home.)
It always has for me, and not in tiny-font or legal language either:
"To help you through your day, Google needs to: Use and store your location for traffic alerts, directions, and more. User your synced calendars, Gmail, Chrome, and Google data for reminders and other suggestions."
This topic does come up a lot here, and yet this is as direct and concise a way to put it as I can imagine. I wonder what those who have been surprised by the services they have opted into would suggest to improve their understanding of what they are potentially agreeing to?
Yes, it is opt-in, which is good. But I feel that for a casual user "use and store your location" doesn't fully get across the point that it's going to track your location in near real-time and make inferences like "this place is your home" about it.
And this is a general problem - people share all kinds of private information about themselves, without full understanding of the kind of analysis that is possible on that data these days.
I personally don't have a problem with the tech (and I've used Latitude way back, so it's not like any of it is new).
(This all without you ever telling which location is your work and which is home.)