Actually that's rather cheaper than a slimline parachute - although I can guarantee that no light aircraft cockpit will be NVG compatible (a big issue in military aircraft approval work). You'd have to turn off the cockpit lights and fly by feel (maybe you'd get a reasonable idea of attitude, maybe not).
The best combination would probably be an NVG monacle combined with a torch blocking the frequencies of light received by the NVG unit.
Actually that would be great fun to try - carefully and under controlled conditions. Does anybody have a set?
G