Do you have any concrete examples of this? I have not seen any myself.

I looked for an alleged case of an LLM apparently reproducing email signatures—but couldn’t find it exactly, and of course many email signatures have been published over the years, especially on newsgroups. (Maybe it was conspiratorial kind of thinking from web commenters assuming ChatGPT was training on emails users were feeding it, which as mentioned certainly doesn’t need to be the case.)

Something like the top screenshot here, though:

https://www.zdnet.com/article/chatgpt-can-leak-source-data-v...

(not parent commenter but) tl;dr no