So - what you saw was automatically generated on your phone, and not uploaded to facebook. It's just displayed on your phone in the newsfeed view, and you can opt-in to having it posted.

This happened to a friend of mine who is an ex-FBer, and he posted on FB about it, and a number of people from the FB team who worked on the mobile app piece of it confirmed that indeed no data had left his phone without him requesting that it be posted, but that they were going to make that behavior more clear in an upcoming release.