Gear auto deploys when the system reaches absolute minimum battery level prior to a system commanded landing. The system has no way of knowing an operator has become incapacitated so all it can do is hover and wait for either a new command or for the battery to discharge to the auto land level. If RTH has been activated and allowed to run its course the gear is auto deployed and the aircraft lands itself.
Easy way to verify the above is go out and test it. You don't have to believe anyone that way, you'll know. Engage RTH and watch what happens. Next flight, set the RTH height, fly out a short distance below RTH height while clear of obstructions and enter Pad mode. At that time the aircraft should climb to the set RTH height and return to the last known position if the ST-16 and hover, awaiting a new command. You have the option of waiting for the battery to discharge to the point the H will self land, or returning to telemetry mode by pressing the home button on the -16 and resuming manual control.