[blooalien]

I had a similar experience back when I was a web dev (in the early days of the web's growing popularity) and some clients would cancel a website project because their teen told them they could do it for them much cheaper with DreamWeaver or MS Word.

Several folks here suggest doing exactly what I did back then, and truth be told, it'll likely work today just as well as it did back then. Tell the customer straight up why it's a bad idea (just be honest and forthright here), and make clear that you'll be charging extra for the very much different skill of cleanup and debugging the "tag soup" garbage that DreamWeaver (or in this case "vibe coding") will produce when it inevitably fails to deliver the result they'd hoped for.

Then step back and find other work while you wait for the windfall as your prediction plays out exactly as you warned them it would. If it doesn't, then "good for them". Be happy for them that they're happy, and be happy for yourself that you found other (less stressful) work. Win-win, either way? Either way, you're working, they're happy with (or at least getting) their hoped-for result, and nobody's stuck with something they didn't really want (other than perhaps your inflated rate for blithely altering the scope of your task).

Fact is that they're paying you for your expertise, and if they choose to ignore that expertise when it really matters, it should cost them to access more valuable expertise when it comes time.