Most Panasonic Lumix's with GPS have a feature where the GPS turns off when the camera is powered down. They call it "Airplane Mode" strangely enough. When the camera is switched on, the GPS kicks back in.
If it's a warm-fix, the time delay is quite small, if you've moved a lot and caused it to have to do a cold-fix the time is quite a bit longer.
The 6D's GPS appears to pull location non-stop until the GPS receiver is turned off, not if the body is switched off. Therefore, if you are storing your 6D, you should turn off GPS before switching it off. I plan on testing mine for battery life in detail over the next few days.