Lynch had to know that she should keep a record when dealing with a Clinton.
The backstory chatter is that Clinton and Lynch were told by security that the meeting was completely clear and clean of any news media, recorders, devices, etc. They thought they were clear to make their plans.
The backstory chatter also says NSA Director Admiral Mike Rogers set up the sting recordings and deliberately miscategorized them in the NSA database as something innocuous so they wouldn’t be noticed and later found.
I believe it when people say that Admiral Rogers literally saved the Republic.