Backround info: Prior to take-off and landing, flight attendants lock the lavatories to discourage passengers from using them while taxing or before reaching cruising altitude. And passengers going to and fro FL are a pain in the ass.
Scene: We've just reached cruising altitude, the captain has turned off the fasten seat belt sign, I'm at the top of the main cabin aisle with the bar cart and the another flight attendant is on the other side. This particular aircraft has a lav just after first class, the door is locked and a man is waiting to go it. In other words, he's standing right behind me.
Passenger, in a huffy tone: Excuse me, why is that man just standing there staring at everyone?
Flight Attendant (not me, the other one) in a normal, unconcerned way: Well, he's probably just waiting to use the bathroom.
F/A: Um... I can go talk to him and find out.
Passenger: You better. I think he's up to something, he looks suspicious. What's his name? Find out his name.
Me: Sir, are you headed back to your seat?
Me: Are you waiting to go in?
HIM: Yeah, I've been waiting like 15 minutes.
Me, to the other F/A: Did you lock the lav before take-off and forget to unlock it?
F/A: Oh yeah...
I knock, no reply, unlock the door, HIM goes in. (He does say thank you). Complete non-issue.
F/A: He was just waiting to use the lavatory. Federal regulations require us to lock them for take-off and landing, and I forgot to unlock it.
Passenger: No. That's not it.
F/A: I assure you, he was just waiting to go to the bathroom.
HIM was darker skinned, I'm not sure if he was Indian dark or African. Nicely dressed in khakis and a yellow button down shirt, well-mannered and polite. Passenger was your classic Italian Jersey older woman, complete with dye job, fake nails, and a crucifix. Also, I'm not quoting exactly here... maybe you had to be there? Just remember stuff that happens in the movies doesn't happen everyday. And if you don't believe W when he tells you that we're winning the war on terror, then vote for someone you believe will kick some terrorist ass!