Here's my DL story from 2009:
I had a very upsetting experience on DL (perhaps one of their regional carriers but I don't remember who....Comair perhaps) going SDF to ATL. GA told us no working toilet and we should "go" before getting on the 1hr 10min scheduled flight. I went to restroom and then boarded. We sat at the SDF gate for 20 minutes waiting for paperwork. I realized that the coffee was only rented and worried that we might also have a delay landing in ATL. I asked the FA how much longer we would be sitting there. She was pleasant, said she didn't know but felt it would be quite soon. She walked to back of plane and I decided to walk forward and tell pilot I had to go inside the terminal to use the restroom. (The cockpit door was open and both pilots were pleasantly willing to talk to me...I did NOT enter the pilots area). The door was open to the jetway however the jetway was pulled back about 10 feet and the steps were down. By that time pilot told me to go to restroom, he was still waiting for paperwork.

FA saw me talking to pilot and almost ran up the aisle! FA said "I'll handle this...you can NOT talk to the pilots!" She then stepped between me and the cockpit. The pilots were as shocked at her eruption as I was. I apologized to her for breaking a protocol and she calmed down. I stood at the door for perhaps 5 minutes waiting for the jetway to be pulled up to the plane (pilots had called GA to bring back the jetway). I assumed everyone in the plane was angry at me and assumed they knew I was causing further delay. At that point the FA picked up the intercom and stated "Ladies and Gentlemen, we'll have a further delay because a passenger has to use the restroom". I'm sure she did this just to embarass me further....and she did!

I went in, used the facility, and returned to the plane within 3 minutes. I then walked down the aisle and was again feeling the eyes of all on board. I sat down and we waited another 10 minutes before leaving the gate. I was glad because the ultimate delay was paperwork not me.

By the time we were nearing ATL I was "over" my embarrassment; but, inwardly I was so glad I had used the restroom. It WAS the right decision.
As the FA was making her final check before landing she walked up to my seat, leaned down close to me and said, without any smile, "I could have you arrested and jailed for talking to the pilots. Remember that the next time you go forward in a plane!" I was shocked....this was at least 1 hour after the incident. She was just trying to get the last word in and show me who is the BOSS!" I kept my cool but was very angry. I realized that, yes, she is the boss and probably could make my trip a nightmare. I didn't say a word, I just looked at her and she left.

That's my story of a Regional Jet with a non operating lav. In hindsight, I did the right thing by keeping my mouth shut when I really wanted to blast her and scream at her. She purposely embarrassed me with her public announcement. I did not write her up but perhaps should have.