Mirrors on the ceiling,
The pink champagne on ice
And she said 'We are all just prisoners here, of our own device'
- Eagles, Hotel California
So a Twitter-friend did me the favor of testing Facebook Places features by checking me.
To test how this works, I had changed none of the setttings that I've been alerting you to check in this post and this one.
Using Places, he checked in to a restaurant where he was not physically present, and tagged myself and another of his Friends at the same restaurant.
The notification I received was:

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Here's what shows up in my Profile:
And here's what showed up on his wall:

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When I go to my FB Home page, at the top of the Newsfeed - both Top News and Most Recent - appears this:

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Clearly, I have the ability to allow check-ins or delay the permission for others to check me in....once I get back to my computer and check my FB notifications, or get an alert on my Droid - if I'm set up that way.
But, regardless, the check-in had already gone out on his wall.
As another friend, Alex de Carvalho (@alexdc) put it on Twitter:

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In another post, I'll follow up with what happens when you allow the check-ins and when you say "Not Now."
For now, just know that you might be getting checked in by your friends to places without your knowing about it until after the news has already gone out.
You can check out any time you like but you can never leave...