I do have one way of telling: my wife's a designer, and she has many artist and designer friends so I see how they work first hand. AI is largely used for edits that need to be done quickly rather than from-scratch generation.
You talk about aesthetics but that's very secondary to communicating the precise thing you want to communicate. AI just isn't there.
Speaking only for myself, that is absolutely accounted into my despair when I see an AI poster. Not just the fact that we're having a wide range of cultural and regional artifacts being stamped out and homogenized by the convenience of AI posters, but the fact that I'm only able to point them out right now because the public backlash is somewhat limited to the online sphere, so most people are okay with the default result it spits out. And we're one default ChatGPT/Claude "curated diversified aesthetic selector" feature away from making my current discernment completely useless.
Of course there's an argument of "if it's so good you can't tell, is there really a problem?", but here I'm responding specifically to the argument of a negative reaction to AI posters not taking the above into account.
Who is imagining that?
> No, you silly geese. What you are able to spot is somebody using AI poorly. That's not you developing taste.
Again, I'm not really sure that the 'spotting AI' endeavour is always supposed to be a flex of someones own taste.
> You have absolutely no way of telling when a good designer created something entirely using AI (unless they are fine with you knowing that) and that has always been true.
I have trouble parsing your entire comment, but you have lost me completely at 'always been true'. I don't know how many hours your 'good designer' would waste on creating only with AI something able to fool everybody 2 years ago. It would surely be too many to be practical.
(Granted, given that you always needed some way of steering the AI and a harness around it, defining "entirely" in this context is a separate, debatable exercise)