It's funny that ChatGPT appears to be self aware about this:

Prompt: How to detect if an answer on Stack Exchange was written by an AI?

There is no definitive answer to this question, as there is no surefire way to determine whether or not an answer was written by an AI. However, some clues that may suggest that an answer was written by an AI include:

The answer was posted very quickly, often within minutes of the question being asked.

The answer is identical or very similar to another answer on the site.

The answer is very short and concise, with little or no explanation or elaboration.

Another thing to look for is the level of detail in the answer. An AI might not provide enough detail to answer the question fully, or it might provide too much detail that is not relevant to the question.

Additionally, if an answer is full of errors or contains nonsensical phrases, it may have been written by an AI.