I wasn't planning on making the jump until the next trailer, but the particularly strong warning on the last bit of news startled me enough.
I have a guess about which of the big three would be most likely to bite it, though I'd rather not read about the specifics ahead of time. There's just no way to imagine what it would have been like to see the three-hilted saber for the first time in the teaser trailer, rather than beforehand online. The moment was less of a, "whoa, what's that?" and more of, "oh, so that rumor was true."
Forming a habit of kneejerking away from spoilers will be tough. I didn't do that at all for the prequels, since we knew what would happen broadly already.