Juliette, 

Are you sure? I tried the service this morning, and I tagged people at a location completely without their knowledge. While it didn&#039;t show up on their wall, it definitely listed them as being present on the location&#039;s page itself. 

So, yes, people can check you in at a place without them being there. The person does not need to already have marked themselves there. 

Hope this helps. 

Keith Whamond