My husband normally uses Skype to communicate with our deaf (foster)son, but recently there was a problem with that. Our son could send video messages through Skype, but couldn't receive them, so my husband was using Relay for his part of the conversation and watching the replies in ASL on his computer. The operator didn't say anything she shouldn't have, but her tone of voice revealed she thought something very strange was going on when my husband kept talking with occasional pauses but there was never a reply from the TDD. When he asked our son to show him something and said he could see it, her voice became even more tense.
Finally, out of sympathy for the poor operator, my husband explained he was watching the replies on his computer screen and neither hallucinating nor using ESP to get them. The woman sounded greatly relieved when she thanked him for explaining.
I laughed when I heard about that conversation, but a hundred, or maybe even fifty years ago if people had known we normally watch each other from hundreds of miles away they would have been amazed. We've certainly come a long way.