Parasitic drain is a serious issue on my FT02, to the point that I regret having bought it, and I regret that I have recommended the light to a collegue. It has killed two batteries now, one of mine and one of my collegue. Locking out the tailcap works nine out of ten times, then you forget it and a week later your battery is down to 1.2V. When a light is off, it must be off.
Still the design and functionality of the FT02 is great, but if they did not fix the parasitic drain, it is not worth buying it IMO.