I have an experienced of a an "interested one" conversing with a DFd person at the hall:
Before I faded away and still went to a few meetings a month we took a friend who was researching different religions to a Sunday meeting(not to convert him, but for him to see how dull it really was). A DFd person that I had grown up with was there also. By coincidence, my interested friend knew my DFd friend. Not knowing the WTS policy on DFing and shunning, he went right up to the DFd person and started talking. I was mildly shocked at first and then thought, well, he's not a JW, he can talk to whoever he wants.
The DFd person was very ill at ease and didn't even get up to shake the other guys hand or carry on much of a conversation. The intersted guy was confused as to why he received what he perceived as a cold shoulder from him. We tried to explain the situation but he didn't understand and I was embarrassed that he was embarrassed and that my DFd friend was embarrassed.
I talked to my DFd friend a few days later(yea, I know, for shame, for shame) and he expressed regret in how he snubbed the other guy who had no idea about the shunning policy. He asked me to apologize for him and said if he had it to do over again he would behave as if they were out in public somewhere and ran into each other.
That was another little light bulb going off in my brain. Another "something ain't right about this" that pushed me further out the door.