The Darwin Awards just got a whole lot more competitive.
The controls, and fundamental aeronautical responses to flight inputs, remain the same in both flight regimes and, for the most part, there's a gradual and manageable amount of pilot feedback during the transition.
In fact, this lack of "gradual feedback" was the main reason that power steering took so long to be safety-approved in automobiles. It's also why, in most countries, pure 'drive-by-wire' controls are only allowed in experimental and prototype road vehicles. Despite the obvious ergonomic and cockpit layout virtues of joysticks, steering wheels and worm gears can still work without active power-assists.
The same can be said for a gliding light airplane or helicopter under auto-rotation.
Alas, the same CAN NOT be said for the Martin jetpack when deploying its ballistic parachute. Btw, aside from cost and liability issues, this is one of the reasons emergency ballistic parachutes haven't caught on in small single-engine aircraft.
Here's a link to an article about the ballistic parachute fitted to Cirrus SR20/22 aircraft. http://www.cirruspilots.org/content/CAPSHistory.aspx There's one mention of a low-altitude parachute deployment: "one activation occurred at too low an altitude to fully inflate the canopy (witnesses report 200 feet above ground), and another activation where the rocket took an unusual trajectory resulting in a failure to open the canopy."
A skydiver is transitioning (abruptly) from unpowered free-fall into unpowered, albeit greatly slowed, descent. The jetpack user is transitioning from powered, controlled horizontal flight (with its characteristic 6 degrees of freedom) into unpowered descent.
A back-up chute for the skydiver has essentially, but not quite, the same flight characteristics and initial deployment conditions as a main.
Parachutes in a stable flight configuration are incredibly safe and reliable, but it's GETTING that 6-axis dynamic flight-body INTO that stable flight configuration that's the real challenge.
It's relatively easy to design a system for even extremely large, static, dead-weights (such as cargo or even battle tanks) to be safely launched, arrested, and landed via parachute.
It's an entirely different problem when your safe chute deployment must take into account the wide variance in airspeed, pitch, yaw, altitude, and environmental influences which powered free flight allows. Imagine a worse-case scenario where all power was lost just after a major inadvertent yaw maneuver (it appears to be designed to minimize yawing). That's a sticky-wicket to solve repeatedly and reliably.