Thought I don't have a high opinion of the elders, I must say that I believe that the majority of them actually do hold to the secrecy and confidentiality. I've known of elders who lost their privileges for breaking such rule and we are all more than angry at them for upholding such confidentiality when it comes to pedophiles.
On the other hand, their family (wife, kids, other people living with them), might not uphold such standards. They might see notes, overhear phone conversations, see emails, etc and than leak these information. For instance, many documents are leaked to the xjw community. Do you believe it is an elder in good standing that is behind such leaks every time?
Then there is also the fact that many sisters confide in elder's wives. So, these conversation, along with the information she can rip from her husband, gives her a lot of power in connecting the dots and spreading the information across.
For instance, perhaps it was even the mother of the 16 year old that confided in an elder's wife.
My point is that though it is possible for elders to speak too much, I sincerely believe they are a minority. Perhaps 1 in 5?