I've also noticed that ChatGPT tends to respond to short prompts, especially questions, in a predictable format. There are a few characteristics.

First, it tends to print a five-paragraph essay, with an introduction, three main points, and a conclusion.

Second, it signposts really well. Each of the body paragraphs is marked with either a bullet point or a number or something else that says "I'm starting a new point."

Third, it always reads like a WikiHow article. There's never any subtle humour or self-deprecation or ironic understatement. It's very straightforward, like an infographic.

It's definitely easy to recognize a ChatGPT response to a simple prompt if the author hasn't taken any measures to disguise it. The conclusion usually has a generic reminder that your mileage may vary and that you should always be careful.