A better title for your post would have been Blueblades and his gulliblity.
Since when can elders promise that they won't disfellowship a person? After all the evidence is heard don't the elders prayerfully seek direction from Jehovah? You were an elder, you knew how the game was played. You knew about "theocratic warfare strategy". You knew JC procedure. You also knew that you weren't the one on the hook...but you let them hook you as well.
There were at least two warnings that you either overlooked or ignored: One, that they called you instead of your son. Can you say "bait"? Two, they told you they would do everything they POSSIBLY could..as in "we have certain limits; either your son remains within them or all that we have held out to you during negotiations loses validity" (as if it ever had validity to begin with!).
It seems that your intent was to act as a shield for your son. If you actually believed in and trusted these men then why did you behave as though your son needed protecting from them?
The onus is on you. Your actions were ambivalent; you delivered your son to persons you weren't sure you could trust (why else would you have been negotiating with them in the first place?).
Those elders didn't lie; you misjudged their position and, imo, overestimated yours.
There is another possibility here, however obscure, and it is that your son told you one story and told them something completely different. Proverbs 26:17: As one grabbing hold of the ears of a dog is anyone passing by that is becoming furious at the quarrel that is not his. Better you should have stayed out of it.
In your original post you asked:
What have elders told you, even given their word and promising you whatever to get you to give out information that they would not otherwise get from you? Have you experienced elders who have done this to you? What did you do about it?
Blue, if you want to have your "ears tickled" then go ahead and look for support among persons who have made the same mistake as yours.
If you want to learn something then ponder the meaning of these words which, I am sure, are familiar: "Do not put your trust in nobles, nor in the son of earthling man, to whom no salvation belongs." (Psalm 146:3)
*Exits, muttering: "...can't see two feet in front of their faces, always looking for someone else to blame...ya think they'd learn but noooo....."