There are bullshitters in the real world, but for the most part they tend to just say "I don't know" in a really convoluted way. They won't, for example, completely fabricate entire concepts and speak confidently and in detail about them.
For example, I asked ChatGPT about the meaning of a non-existing verb ("to spoink"). It originally said the word didn't exist, but when I said "are you sure? we talked about it before, it's something to do with trifle" it invented an entire episode of the IT Crowd (Season 3, Episode 3), talked at length about how that word appeared twice. It claimed that one character - Moss - created it as the sound a metal ball would make if it hit a hard surface, and also that it's what happens when you leave a trifle out uncovered in the open and it goes lumpy. It's creative, but it's nonsense.
Very few humans could pull this off convincingly or would even attempt it. They would say "no we didn't talk about the verb 'to spoink' that sounds like nonsense".
Haha :D Honestly though, if creative writing and absurd humour was the goal, they absolutely nailed it. I was particularly impressed with the onomatopoeia of the first “spoink” definition