That reminds me, in my first induced LD ever (which lasted seconds, mind you), I told my mother “hmm, I… think I may be dreaming” (I love to recall the doubt and shyness there 
, her answer was a very interested "reeeeeeeeeeeeally? 
Had a LD this night and told a DC that it is a dream. The DC simply answered: “Yeah, I know”. I expected some sort of an angry answer, being called stupid and insane. It seems that some DC’s accept the fact that it is a dream pretty easily 
Once I was in the middle of having sex with a DC and told them it was a dream. They just totally ignored me and we carried on.
Yeah. When I used to have dreams when I was little and i became lucid, I was telling everyone “HAHAHAHAHAHA you faker! I’m in a dream!” and they’d deny it and they’d cry because they wanted to be more than just a dream. But it’s really and scary telling them they’re in a dream. I feel so lonely after I realize it’s all fake. 
I love doing this. One of the most interesting responses I got was when I told a (DC version of a) friend that we were in my lucid dream. She laughed and became very interested in how it worked, peppering me with questions like,
“So, we’re both dreaming? No? How’s this work then? Will I remember this tomorrow?”
“You mean, I’m not real and you are? This is your dream? That’s hilarious.”
“What’s going to happen to me after you wake up?” (This one left me fumbling for an answer.)
In another instance, a DC responded by saying, “I hope they don’t have to amputate.” 
“Yeah, lucid dreams that last for too long cause a total loss of circulation in the dreamer’s limbs, limb necrosis and eventually require amputation.”
“It’s really terrible,” he added helpfully.
I didn’t believe him, but I’ll admit that one shook me up a little. I guess my subconscious likes to have a laugh at my expense sometimes! 
I did it just once. I was lucid from the very start and I met my dead neighbour in the corridor in my flat. I told her it was a dream. She said something, but I wasn’t able to hear her. And while I’m not an experienced dreamer a knocking behind my door distracted me. I can’t say whether I was still lucid or I lost awareness of dreaming.
I was in my school and I told a DC of a girl I knew IRL that this was all a dream (I was lucid on a fairly low level) and she said ‘True’, but I somehow got the feeling she still didn’t believe me. There was a water heater with a loose piece of tape on it in the room we were in and I somehow got the crazy idea to turn it into a little stream of water so I did but she ether didn’t see it or didn’t care.