We could do that same thing. The iPad is in the mail room...not a door you have to pass through to leave.
I'm not even in the building. I can come and go as I please. The only way they can log me is my computer use or the cameras on the equipment yard, as I park in back. So I could go clock in, drvie off...come back later and clock out. The only read flag is that I'm half expected to be online (software, lisps, tutorials, etc), so if they don't see me online, they'll pull my computer activity and see none an go from there. Surveillance on the yard would see me come and go.