Yeah you won't be able to escape a label of "Apostate" when you write a DA letter. Leaving the organization formally constitutes apostasy, period. It's incredibly asinine, but there it is.
I would hesitate to say it was the lights, only because I've seen PLENTY of JW's, elders and their wives included, who have white lights strung around their home or property year-round. If you're on any type of social media (such as Facebook or Twitter) and have posted about anything having to do with your life that is "unbecoming of a JW", then that would be my first guess. Many have been nabbed because they posted something on Facebook and an elder got wind of it. It's so easy to copy and paste or screen shot, so ANYONE who was snooping could have gotten information and passed it on. I've been a victim of it myself and refused to meet with the elders about it...Nothing ever came of it and I remain just a fader, no formal disassociation or DF'ing took place.
If you've got nothing to lose, go for it. Personally, I'd rather not give in to their little political game.