Mild as it was, the lows weren't too much lower than normal, there were just more warm days. In terms of temperature damage, I suspect they'll be fine next winter too, but we'll see. From a purely selfish POV, I only really care if they get through next winter, because after that I'll be elsewhere and have a different winter to acclimate them to.
Also, I recently bought the e-book from cobraplant.com, and they showed pots of flytraps absolutely frozen solid, then coming back in perfect form the next year (which is actually what inspired me to leave my plants outside rather than put them in the fridge. Anecdotally, the plants seem a lot more vigorous this spring than last.
I actually split my fltrap into 4 this year, so perhaps next winter I'll put two outside and two in the fridge, and see which does better the next growing season.
Mokele