When they think it’s off the record. LOL
Personally, I am very circumspect in my emails. I can't believe some of the emails I see other paralegals send out because they are lazy. Sometimes they give away the farm and sometimes they practice unauthorized practice of law - and it's in writing, yet.
If I need to communicate with the other side, I always do it in a piece of careful, formal correspondence (no phone calls, a waste of time). And I ALWAYS keep the fax transmission receipt. That has saved my hide more than once!