Give us a "check out" feature...

I see a lot of people checking in to a location that they were already checked in to. I suspect this means they check in in the morning, go to lunch, and then check in again when they get back from wherever they went to lunch.

Seems like a good idea to let people "check out" of a location, if they know they're going to be gone for an extended period but not check in to a new location during that absence. This way, I don't show up somewhere, expecting to see someone who isn't actually there, despite being checked-in.