Examiners at the USPTO have now been directed to make all information sent to them of record (attached to an interview summary) even if you explicitly indicate that the information is for discussion purposes only, for example in an interview. What this cautionary tale should teach us is that now more than ever any communication with Examiners should be strictly oral when possible.
My concern with this new policy is how will the court system treat "proposed claim amendments?" Will these proposed claim amendments also be viewed under prosecution estoppel? In other words, is this ground that will be deemed as relinquished to the public since the amendments were proposed and subsequently made of record? If so, I fear that interview practice at the USPTO will significantly suffer. It is much more difficult to discuss possible claim amendments with an Examiner if sharing documents in advance creates a record.
Proceed with caution folks - and hope that what I stated above will not be the case.